Interworking with legacy radio access technologies for connectivity to next generation core network

ABSTRACT

Aspects of the disclosure relate to mechanisms for interworking between legacy and next generation radio access technologies (RATs) in a communication network. In some examples, a handover from a next generation access network to a legacy access network may be performed via a next generation core network and a legacy core network. A handover request received at a next generation core network serving node may include an identifier of a target cell within the legacy access network. The next generation core network serving node may identify a legacy core network serving node to which the handover may be forwarded based on the target cell identifier. Packet data units may then be routed over the legacy access network and the next generation core network by mapping data flows in the next generation core network to packet data connections in the legacy access network.

PRIORITY CLAIM

The present Application for Patent is a Divisional of U.S. patentapplication Ser. No. 15/430,408 filed in the U.S. Patent and TrademarkOffice on Feb. 10, 2017, the entire content of which is incorporatedherein by reference as if fully set forth below in its entirety and forall applicable purposes. U.S. patent application Ser. No. 15/430,408claims priority to and the benefit of Provisional Patent Application No.62/317,414 filed in the U.S. Patent and Trademark Office on Apr. 1,2016, the entire content of which is incorporated herein by reference asif fully set forth below in its entirety and for all applicablepurposes.

TECHNICAL FIELD

The technology discussed below relates generally to wirelesscommunication networks, and more particularly, to interworking withlegacy radio access technologies. Embodiments can enable techniques forproviding connectivity to next generation core networks.

INTRODUCTION

Wireless access networks are widely deployed to provide various wirelesscommunication services such as telephony, video, data, messaging,broadcasts, and so on. Wireless access networks may be connected toother wireless access networks and to core networks to provide variousservices, such as Internet access.

For example, current fourth generation (4G) wireless access and corenetworks, such as the Long Term Evolution (LTE) network, provideInternet Protocol (IP) packet-switching services that may supportwireless downlink data rates up to 1 Gbit/second. However, plans areunderway to develop new fifth generation (5G) networks that will supporteven higher data rates and increased traffic capacity, while alsosupporting different types of devices (i.e., Machine-to-Machine) andproviding lower latency.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a simplified summary of one or more aspects ofthe present disclosure, in order to provide a basic understanding ofsuch aspects. This summary is not an extensive overview of allcontemplated features of the disclosure, and is intended neither toidentify key or critical elements of all aspects of the disclosure norto delineate the scope of any or all aspects of the disclosure. Its solepurpose is to present some concepts of one or more aspects of thedisclosure in a simplified form as a prelude to the more detaileddescription that is presented later.

Various aspects of the disclosure relate to mechanisms for interworkingbetween legacy and next generation radio access technologies (RATs) in acommunication network. In some examples, a connectivity requestoriginated by a user equipment towards a legacy core network may betransferred to a next generation core network. This can occur when theuser equipment supports the RAT of the next generation core network. Insome examples, a connectivity request originated by a user equipmenttowards a next generation core network may be processed by the nextgeneration core network. In some examples, a handover from a legacyaccess network to a next generation access network may be performed viaa next generation core network and a legacy core network. In someexamples, a handover from a next generation access network to a legacyaccess network may be performed via a next generation core network and alegacy core network.

In one aspect, a method for interworking between radio accesstechnologies in a communication network is provided. The method includesreceiving mapping information for a user equipment at a core networkserving node within a core network supporting a first radio accesstechnology (RAT) after handover of the user equipment from the first RATto a second RAT. The mapping information indicates a mapping between oneor more data flows within one or more Data Network Session (DNS)connections for communicating over the core network and one or morecorresponding Generic Tunneling Protocol (GTP) tunnels within one ormore corresponding Packet Data Network (PDN) connections forcommunicating over a wireless access network utilizing the second RAT.The method further includes receiving a packet data unit (PDU) at thecore network serving node. If the PDU is an uplink PDU, the methodfurther includes decapsulating the uplink PDU from a GTP tunnel of theone or more GTP tunnels within a PDN connection of the one or more PDNconnections to produce a decapsulated PDU, mapping the decapsulated PDUto a data flow of the one or more data flows based on the mappinginformation to produce a data flow PDU, and routing the data flow PDU toa user plane gateway serving the data flow within the core network.

Another aspect of the disclosure provides an interworking core networkserving node for interworking between a first core network supporting afirst radio access technology (RAT) and a second core network supportinga second RAT. The interworking core network serving node includes aninterface coupled to a wireless access network that utilizes the secondRAT, a memory, and a processor communicatively coupled to the interfaceand the memory. The processor is configured to receive mappinginformation for a user equipment after handover of the user equipmentfrom the first RAT to the second RAT. The mapping information indicatesa mapping between one or more data flows within one or more Data NetworkSession (DNS) connections for communicating over the first core networkand one or more corresponding Generic Tunneling Protocol (GTP) tunnelswithin one or more corresponding Packet Data Network (PDN) connectionsfor communicating over the wireless access network. The processor isfurther configured to receive a packet data unit (PDU), and if the PDUis an uplink PDU, decapsulate the uplink PDU from a GTP tunnel of theone or more GTP tunnels within a PDN connection of the one or more PDNconnections to produce a decapsulated PDU, map the decapsulated PDU to adata flow of the one or more data flows based on the mapping informationto produce a data flow PDU, and route the data flow PDU to a user planegateway serving the data flow within the first core network.

Another aspect of the disclosure provides an interworking core networkserving node apparatus for interworking between a first core networksupporting a first radio access technology (RAT) and a second corenetwork supporting a second RAT. The interworking core network servingnode apparatus includes means for receiving mapping information for auser equipment after handover of the user equipment from the first RATto the second RAT. The mapping information indicates a mapping betweenone or more data flows within one or more Data Network Session (DNS)connections for communicating over the first core network and one ormore corresponding Generic Tunneling Protocol (GTP) tunnels within oneor more corresponding Packet Data Network (PDN) connections forcommunicating over a wireless access network utilizing the second RAT.The interworking core network serving node apparatus further includesmeans for receiving a packet data unit (PDU). If the PDU is an uplinkPDU, the interworking core network serving node apparatus furtherincludes means for decapsulating the uplink PDU from a GTP tunnel of theone or more GTP tunnels within a PDN connection of the one or more PDNconnections to produce a decapsulated PDU, means for mapping thedecapsulated PDU to a data flow of the one or more data flows based onthe mapping information to produce a data flow PDU, and means forrouting the data flow PDU to a user plane gateway serving the data flowwithin the first core network.

Another aspect of the disclosure provides a non-transitorycomputer-readable medium storing computer-executable code, includingcode for causing an interworking serving node for interworking between afirst core network supporting a first radio access technology (RAT) anda second core network supporting a second RAT to receive mappinginformation for a user equipment after handover of the user equipmentfrom the first RAT to the second RAT. The mapping information indicatesa mapping between one or more data flows within one or more Data NetworkSession (DNS) connections for communicating over the first core networkand one or more corresponding Generic Tunneling Protocol (GTP) tunnelswithin one or more corresponding Packet Data Network (PDN) connectionsfor communicating over the wireless access network. The non-transitorycomputer-readable medium further includes code for causing theinterworking serving node to receive a packet data unit (PDU), and ifthe PDU is an uplink PDU, decapsulate the uplink PDU from a GTP tunnelof the one or more GTP tunnels within a PDN connection of the one ormore PDN connections to produce a decapsulated PDU, map the decapsulatedPDU to a data flow of the one or more data flows based on the mappinginformation to produce a data flow PDU, and route the data flow PDU to auser plane gateway serving the data flow within the first core network.

Examples of additional aspects of the disclosure follow. In some aspectsof the disclosure, the method further includes, if the PDU is a downlinkPDU of a data flow of the one or more data flows, mapping the downlinkPDU to a GTP tunnel of the one or more GTP tunnels and a PDN connectionof the one or more PDN connections based on the mapping information,encapsulating the downlink PDU into a PDN PDU, and routing the PDN PDUover the GTP tunnel within the PDN connection to the user equipment viathe wireless access network.

In some aspects of the disclosure, each of the data flows is associatedwith a different Internet Protocol (IP) address of the user equipmentutilized in the core network, and each of the corresponding PDNconnections is associated with an additional different IP address of theuser equipment utilized in the wireless access network. In someexamples, a first PDN connection includes two or more of the data flows,each mapped to a different corresponding GTP tunnel within the first PDNconnection.

In some aspects of the disclosure, the method further includes receivingadditional mapping information indicating an additional mapping betweena set of two or more data flows mapped to a first PDN connection to twoor more additional GTP tunnels within the core network, where each ofthe two or more additional GTP tunnels provides connectivity to adifferent user plane gateway in the core network. In some aspects of thedisclosure, the method further includes routing the data flow PDU overan additional GTP tunnel of the one or more additional GTP tunnels basedon the additional mapping information.

These and other aspects of the invention will become more fullyunderstood upon a review of the detailed description, which follows.Other aspects, features, and embodiments of the present invention willbecome apparent to those of ordinary skill in the art, upon reviewingthe following description of specific, exemplary embodiments of thepresent invention in conjunction with the accompanying figures. Whilefeatures of the present invention may be discussed relative to certainembodiments and figures below, all embodiments of the present inventioncan include one or more of the advantageous features discussed herein.In other words, while one or more embodiments may be discussed as havingcertain advantageous features, one or more of such features may also beused in accordance with the various embodiments of the inventiondiscussed herein. In similar fashion, while exemplary embodiments may bediscussed below as device, system, or method embodiments it should beunderstood that such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram illustrating an example of a wirelessaccess network.

FIG. 2 is a diagram illustrating an example of a network architecture.

FIG. 3 is a diagram illustrating exemplary connectivity to a nextgeneration core network over a legacy wireless access network.

FIG. 4 is a diagram illustrating connectivity to a next generation corenetwork over a next generation wireless access network.

FIG. 5 is a diagram illustrating exemplary data network sessionsestablished over a next generation communication network.

FIG. 6 is a diagram illustrating exemplary data network sessionsestablished over a next generation network that is capable ofinterworking with a legacy network.

FIG. 7 is a diagram illustrating an exemplary interworking scenariobetween legacy and next generation networks to handover next generationdata network sessions to a legacy wireless access network.

FIG. 8 is a diagram illustrating another exemplary interworking scenariobetween legacy and next generation networks to handover next generationdata network sessions to a legacy wireless access network.

FIG. 9 is a signaling diagram illustrating exemplary signaling forperforming a handover from a next generation access network to a legacyaccess network.

FIG. 10 is a signaling diagram illustrating exemplary signaling forperforming a handover from a legacy access network to a next generationaccess network.

FIG. 11 is a block diagram conceptually illustrating an example of acore network serving node according to some embodiments.

FIG. 12 is a block diagram conceptually illustrating an example of auser equipment according to some embodiments.

FIG. 13 is a flow chart of a method for interworking between corenetworks in a communication network.

FIG. 14 is a flow chart of another method for interworking between corenetworks in a communication network.

FIG. 15 is a flow chart of another method for interworking between corenetworks in a communication network.

FIG. 16 is a flow chart of another method for interworking between corenetworks in a communication network.

FIG. 17 is a flow chart of another method for interworking between corenetworks in a communication network.

FIG. 18 is a flow chart of another method for interworking between corenetworks in a communication network.

FIG. 19 is a flow chart of another method for interworking between corenetworks in a communication network.

FIG. 20 is a flow chart of another method for establishing connectivityto a next generation communication network.

FIG. 21 is a flow chart of another method for establishing connectivityto a next generation communication network.

FIG. 22 is a flow chart of a method for performing a handover betweencore networks in a communication network.

FIG. 23 is a flow chart of another method for performing a handoverbetween core networks in a communication network.

FIG. 24 is a flow chart of another method for performing a handoverbetween core networks in a communication network.

FIG. 25 is a flow chart of a method for routing IP flows afterperforming a handover between core networks in a communication network.

FIG. 26 is a flow chart of another method for performing a handoverbetween core networks in a communication network.

FIG. 27 is a flow chart of another method for performing a handoverbetween core networks in a communication network.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

The various concepts presented throughout this disclosure may beimplemented across a broad variety of telecommunication systems, networkarchitectures, and communication standards. Referring now to FIG. 1, asan illustrative example without limitation, a simplified schematicillustration of a wireless access network 100 is provided. The wirelessaccess network 100 may be a legacy access network utilizing a legacyradio access technology (RAT) or a next generation access networkutilizing a next generation RAT. The wireless access network 100 mayfurther be coupled to a core network (not shown), which may also be alegacy core network or next generation core network.

As used herein, the term legacy access network, legacy core network, orlegacy RAT refers to a network or RAT employing a third generation (3G)wireless communication technology based on a set of standards thatcomplies with the International Mobile Telecommunications-2000(IMT-2000) specifications or a fourth generation (4G) wirelesscommunication technology based on a set of standards that comply withthe International Mobile Telecommunications Advanced (ITU-Advanced)specification. For example, some the standards promulgated by the 3^(rd)Generation Partnership Project (3GPP) and the 3^(rd) GenerationPartnership Project 2 (3GPP2) may comply with IMT-2000 and/orITU-Advanced. Examples of such legacy standards defined by the 3^(rd)Generation Partnership Project (3GPP) include, but are not limited to,Long-Term Evolution (LTE), LTE-Advanced, Evolved Packet System (EPS),and Universal Mobile Telecommunication System (UMTS). Additionalexamples of various radio access technologies based on one or more ofthe above-listed 3GPP standards include, but are not limited to,Universal Terrestrial Radio Access (UTRA), Evolved Universal TerrestrialRadio Access (eUTRA), General Packet Radio Service (GPRS) and EnhancedData Rates for GSM Evolution (EDGE). Examples of such legacy standardsdefined by the 3^(rd) Generation Partnership Project 2 (3GPP2) include,but are not limited to, CDMA2000 and Ultra Mobile Broadband (UMB). Otherexamples of standards employing 3G/4G wireless communication technologyinclude the IEEE 802.16 (WiMAX) standard and other suitable standards.

As further used herein, the term next generation access network, nextgeneration core network, or next generation RAT generally refers to anetwork or RAT employing continued evolved wireless communicationtechnologies. This may include, for example, a fifth generation (5G)wireless communication technology based on a set of standards. Thestandards may comply with the guidelines set forth in the 5G White Paperpublished by the Next Generation Mobile Networks (NGMN) Alliance on Feb.17, 2015. For example, standards that may be defined by the 3GPPfollowing LTE-Advanced or by the 3GPP2 following CDMA2000 may complywith the NGMN Alliance 5G White Paper. Standards may also includepre-3GPP efforts specified by Verizon Technical Forum (www.vztgf) andKorea Telecom SIG (www.kt5g.org).

The geographic region covered by the access network 100 may be dividedinto a number of cellular regions (cells) that can be uniquelyidentified by a user equipment (UE) based on an identificationbroadcasted over a geographical from one access point or base station.FIG. 1 illustrates macrocells 102, 104, and 106, and a small cell 108,each of which may include one or more sectors. A sector is a sub-area ofa cell. All sectors within one cell are served by the same base station.A radio link within a sector can be identified by a single logicalidentification belonging to that sector. In a cell that is divided intosectors, the multiple sectors within a cell can be formed by groups ofantennas with each antenna responsible for communication with UEs in aportion of the cell.

In general, a base station (BS) serves each cell. Broadly, a basestation is a network element in a radio access network responsible forradio transmission and reception in one or more cells to or from a UE. ABS may also be referred to by those skilled in the art as a basetransceiver station (BTS), a radio base station, a radio transceiver, atransceiver function, a basic service set (BSS), an extended service set(ESS), an access point (AP), a Node B (NB), an eNode B (eNB), a GNodeBor some other suitable terminology.

In FIG. 1, two high-power base stations 110 and 112 are shown in cells102 and 104; and a third high-power base station 114 is showncontrolling a remote radio head (RRH) 116 in cell 106. That is, a basestation can have an integrated antenna or can be connected to an antennaor RRH by feeder cables. In the illustrated example, the cells 102, 104,and 106 may be referred to as macrocells, as the high-power basestations 110, 112, and 114 support cells having a large size. Further, alow-power base station 118 is shown in the small cell 108 (e.g., amicrocell, picocell, femtocell, home base station, home Node B, homeeNode B, etc.) which may overlap with one or more macrocells. In thisexample, the cell 108 may be referred to as a small cell, as thelow-power base station 118 supports a cell having a relatively smallsize. Cell sizing can be done according to system design as well ascomponent constraints. It is to be understood that the access network100 may include any number of wireless base stations and cells. Further,a relay node may be deployed to extend the size or coverage area of agiven cell. The base stations 110, 112, 114, 118 provide wireless accesspoints to a core network for any number of mobile apparatuses.

FIG. 1 further includes a quadcopter or drone 120, which may beconfigured to function as a base station. That is, in some examples, acell may not necessarily be stationary, and the geographic area of thecell may move according to the location of a mobile base station such asthe quadcopter 120.

In general, base stations may include a backhaul interface forcommunication with a backhaul portion of the network. The backhaul mayprovide a link between a base station and a core network, and in someexamples, the backhaul may provide interconnection between therespective base stations. The core network is a part of a wirelesscommunication system that is generally independent of the radio accesstechnology used in the radio access network. Various types of backhaulinterfaces may be employed, such as a direct physical connection, avirtual network, or the like using any suitable transport network. Somebase stations may be configured as integrated access and backhaul (IAB)nodes, where the wireless spectrum may be used both for access links(i.e., wireless links with UEs), and for backhaul links. This scheme issometimes referred to as wireless self-backhauling. By using wirelessself-backhauling, rather than requiring each new base station deploymentto be outfitted with its own hard-wired backhaul connection, thewireless spectrum utilized for communication between the base stationand UE may be leveraged for backhaul communication, enabling fast andeasy deployment of highly dense small cell networks.

The access network 100 is illustrated supporting wireless communicationfor multiple mobile apparatuses. A mobile apparatus is commonly referredto as user equipment (UE) in standards and specifications promulgated bythe 3rd Generation Partnership Project (3GPP), but may also be referredto by those skilled in the art as a mobile station (MS), a subscriberstation, a mobile unit, a subscriber unit, a wireless unit, a remoteunit, a mobile device, a wireless device, a wireless communicationsdevice, a remote device, a mobile subscriber station, an access terminal(AT), a mobile terminal, a wireless terminal, a remote terminal, ahandset, a terminal, a user agent, a mobile client, a client, or someother suitable terminology. A UE may be an apparatus that provides auser with access to network services.

Within the present document, a “mobile” apparatus need not necessarilyhave a capability to move, and may be stationary. The term mobileapparatus or mobile device broadly refers to a diverse array of devicesand technologies. For example, some non-limiting examples of a mobileapparatus include a mobile, a cellular (cell) phone, a smart phone, asession initiation protocol (SIP) phone, a laptop, a personal computer(PC), a notebook, a netbook, a smartbook, a tablet, a personal digitalassistant (PDA), and a broad array of embedded systems, e.g.,corresponding to an “Internet of things” (IoT). A mobile apparatus mayadditionally be an automotive or other transportation vehicle, a remotesensor or actuator, a robot or robotics device, a satellite radio, aglobal positioning system (GPS) device, an object tracking device, adrone, a multi-copter, a quad-copter, a remote control device, aconsumer and/or wearable device, such as eyewear, a wearable camera, avirtual reality device, a smart watch, a health or fitness tracker, adigital audio player (e.g., MP3 player), a camera, a game console, etc.A mobile apparatus may additionally be a digital home or smart homedevice such as a home audio, video, and/or multimedia device, anappliance, a vending machine, intelligent lighting, a home securitysystem, a smart meter, etc. A mobile apparatus may additionally be asmart energy device, a security device, a solar panel or solar array, amunicipal infrastructure device controlling electric power (e.g., asmart grid), lighting, water, etc.; an industrial automation andenterprise device; a logistics controller; agricultural equipment;military defense equipment, vehicles, aircraft, ships, and weaponry,etc. Still further, a mobile apparatus may provide for connectedmedicine or telemedicine support, i.e., health care at a distance.Telehealth devices may include telehealth monitoring devices andtelehealth administration devices, whose communication may be givenpreferential treatment or prioritized access over other types ofinformation, e.g., in terms of prioritized access for transport ofcritical service user data traffic, and/or relevant QoS for transport ofcritical service user data traffic.

Within the access network 100, the cells may include UEs that may be incommunication with one or more sectors of each cell. For example, UEs122 and 124 may be in communication with base station 110; UEs 126 and128 may be in communication with base station 112; UEs 130 and 132 maybe in communication with base station 114 by way of RRH 116; UE 134 maybe in communication with low-power base station 118; and UE 136 may bein communication with mobile base station 120. Here, each base station110, 112, 114, 118, and 120 may be configured to provide an access pointto a core network (not shown) for all the UEs in the respective cells.

In another example, a mobile network node (e.g., quadcopter 120) may beconfigured to function as a UE. For example, the quadcopter 120 mayoperate within cell 102 by communicating with base station 110. In someaspects of the disclosure, two or more UE (e.g., UEs 126 and 128) maycommunicate with each other using peer to peer (P2P) or sidelink signals127 without relaying that communication through a base station (e.g.,base station 112).

Unicast or broadcast transmissions of control information and/or userdata traffic from a base station (e.g., base station 110) to one or moreUEs (e.g., UEs 122 and 124) may be referred to as downlink (DL)transmission, while transmissions of control information and/or userdata traffic originating at a UE (e.g., UE 122) may be referred to asuplink (UL) transmissions. In addition, the uplink and/or downlinkcontrol information and/or user data traffic may be transmitted inslots, which may each include a certain number of symbols of variableduration. For example, the symbol duration may vary based on the cyclicprefix (e.g., normal or extended) and the numerology (e.g., sub-carrierspacing) of the symbol. In some examples, a slot may include one or moremini-slots, which may refer to an encapsulated set of informationcapable of being independently decoded. One or more slots may be groupedtogether into a subframe. In addition, multiple subframes may be groupedtogether to form a single frame or radio frame. Any suitable number ofsubframes may occupy a frame. In addition, a slot or subframe may haveany suitable duration (e.g., 250 μs, 500 μs, 1 ms, etc.).

The air interface in the access network 100 may utilize one or moremultiplexing and multiple access algorithms to enable simultaneouscommunication of the various devices. For example, multiple access foruplink (UL) or reverse link transmissions from UEs 122 and 124 to basestation 110 may be provided utilizing time division multiple access(TDMA), code division multiple access (CDMA), frequency divisionmultiple access (FDMA), orthogonal frequency division multiple access(OFDMA), sparse code multiple access (SCMA), single-carrier frequencydivision multiple access (SC-FDMA), resource spread multiple access(RSMA), or other suitable multiple access schemes. Further, multiplexingdownlink (DL) or forward link transmissions from the base station 110 toUEs 122 and 124 may be provided utilizing time division multiplexing(TDM), code division multiplexing (CDM), frequency division multiplexing(FDM), orthogonal frequency division multiplexing (OFDM), sparse codemultiplexing (SCM), single-carrier frequency division multiplexing(SC-FDM) or other suitable multiplexing schemes.

Further, the air interface in the access network 100 may utilize one ormore duplexing algorithms. Duplex refers to a point-to-pointcommunication link where both endpoints can communicate with one anotherin both directions. Full duplex means both endpoints can simultaneouslycommunicate with one another. Half duplex means only one endpoint cansend information to the other at a time. In a wireless link, a fullduplex channel generally relies on physical isolation of a transmitterand receiver, and suitable interference cancellation technologies. Fullduplex emulation is frequently implemented for wireless links byutilizing frequency division duplex (FDD) or time division duplex (TDD).In FDD, transmissions in different directions operate at differentcarrier frequencies. In TDD, transmissions in different directions on agiven channel are separated from one another using time divisionmultiplexing. That is, at some times the channel is dedicated fortransmissions in one direction, while at other times the channel isdedicated for transmissions in the other direction, where the directionmay change very rapidly, e.g., several times per subframe.

In the radio access network 100, the ability for a UE to communicatewhile moving, independent of their location, is referred to as mobility.The various physical channels between the UE and the radio accessnetwork are generally set up, maintained, and released under the controlof a mobility management entity (MME). In various aspects of thedisclosure, an access network 100 may utilize DL-based mobility orUL-based mobility to enable mobility and handovers (i.e., the transferof a UE's connection from one radio channel to another). In a networkconfigured for DL-based mobility, during a call with a schedulingentity, or at any other time, a UE may monitor various parameters of thesignal from its serving cell as well as various parameters ofneighboring cells. Depending on the quality of these parameters, the UEmay maintain communication with one or more of the neighboring cells.During this time, if the UE moves from one cell to another, or if signalquality from a neighboring cell exceeds that from the serving cell for agiven amount of time, the UE may undertake a handoff or handover fromthe serving cell to the neighboring (target) cell. For example, UE 124may move from the geographic area corresponding to its serving cell 102to the geographic area corresponding to a neighbor cell 106. When thesignal strength or quality from the neighbor cell 106 exceeds that ofits serving cell 102 for a given amount of time, the UE 124 may transmita reporting message to its serving base station 110 indicating thiscondition. In response, the UE 124 may receive a handover command, andthe UE may undergo a handover to the cell 106.

In a network configured for UL-based mobility, UL reference signals fromeach UE may be utilized by the network to select a serving cell for eachUE. In some examples, the base stations 110, 112, and 114/116 maybroadcast unified synchronization signals (e.g., unified PrimarySynchronization Signals (PSSs), unified Secondary SynchronizationSignals (SSSs) and unified Physical Broadcast Channels (PBCH)). The UEs122, 124, 126, 128, 130, and 132 may receive the unified synchronizationsignals, derive the carrier frequency and subframe timing from thesynchronization signals, and in response to deriving timing, transmit anuplink pilot or reference signal. The uplink pilot signal transmitted bya UE (e.g., UE 124) may be concurrently received by two or more cells(e.g., base stations 110 and 114/116) within the access network 100.Each of the cells may measure a strength of the pilot signal, and theaccess network (e.g., one or more of the base stations 110 and 114/116and/or a central node within the core network) may determine a servingcell for the UE 124. As the UE 124 moves through the access network 100,the network may continue to monitor the uplink pilot signal transmittedby the UE 124. When the signal strength or quality of the pilot signalmeasured by a neighboring cell exceeds that of the signal strength orquality measured by the serving cell, the network 100 may handover theUE 124 from the serving cell to the neighboring cell, with or withoutinforming the UE 124.

Although the synchronization signal transmitted by the base stations110, 112, and 114/116 may be unified, the synchronization signal may notidentify a particular cell, but rather may identify a zone of multiplecells operating on the same frequency and/or with the same timing. Theuse of zones in 5G networks or other next generation communicationnetworks enables the uplink-based mobility framework and improves theefficiency of both the UE and the network, since the number of mobilitymessages that need to be exchanged between the UE and the network may bereduced.

In various implementations, the air interface in the access network 100may utilize licensed spectrum, unlicensed spectrum, or shared spectrum.Licensed spectrum provides for exclusive use of a portion of thespectrum, generally by virtue of a mobile network operator purchasing alicense from a government regulatory body. Unlicensed spectrum providesfor shared use of a portion of the spectrum without need for agovernment-granted license. While compliance with some technical rulesis generally still required to access unlicensed spectrum, generally,any operator or device may gain access. Shared spectrum may fall betweenlicensed and unlicensed spectrum, wherein technical rules or limitationsmay be required to access the spectrum, but the spectrum may still beshared by multiple operators and/or multiple RATs. For example, theholder of a license for a portion of licensed spectrum may providelicensed shared access (LSA) to share that spectrum with other parties,e.g., with suitable licensee-determined conditions to gain access.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. Within the present disclosure, as discussed further below,the scheduling entity may be responsible for scheduling, assigning,reconfiguring, and releasing resources for one or more subordinateentities. That is, for scheduled communication, subordinate entitiesutilize resources allocated by the scheduling entity.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources (e.g.,time-frequency resources) for communication among some or all devicesand equipment within its service area or cell. Within the presentdisclosure, as discussed further below, the scheduling entity may beresponsible for scheduling, assigning, reconfiguring, and releasingresources for one or more scheduled entities. That is, for scheduledcommunication, UEs or scheduled entities utilize resources allocated bythe scheduling entity.

Base stations are not the only entities that may function as ascheduling entity. That is, in some examples, a UE may function as ascheduling entity, scheduling resources for one or more scheduledentities (e.g., one or more other UEs). In other examples, sidelinksignals may be used between UEs without necessarily relying onscheduling or control information from a base station. For example, UE138 is illustrated communicating with UEs 140 and 142. In some examples,the UE 138 is functioning as a scheduling entity or a primary sidelinkdevice, and UEs 140 and 142 may function as a scheduled entity or anon-primary (e.g., secondary) sidelink device. In still another example,a UE may function as a scheduling entity in a device-to-device (D2D),peer-to-peer (P2P), or vehicle-to-vehicle (V2V) network, and/or in amesh network. In a mesh network example, UEs 140 and 142 may optionallycommunicate directly with one another in addition to communicating withthe scheduling entity 138.

FIG. 2 is a block diagram illustrating an example of a networkarchitecture 200 employing both legacy (e.g., 3G and/or 4G) and nextgeneration (e.g., 5G) communication networks. The network architecture200 may include one or more user equipment (UE) 202, a legacy (3G or 4G)wireless access network (AN) 204, a next generation (5G) wireless AN206, a legacy (3G or 4G) core network 232 and a next generation (5G)core network 208.

In this illustration, as well as in FIGS. 3-8, any signal path between aUE and a core network is presumed to be passed between these entities byan access network, as represented by an illustrated signal path crossingthe access network. Here, the access networks 204 and 206 may each bethe access network 100 described above and illustrated in FIG. 1. In thedescription that follows, when reference is made to an access network(AN) or actions performed by the AN, it may be understood that suchreference refers to one or more network nodes in the AN that is or arecommunicatively coupled to a core network e.g., via a backhaulconnection. As one nonlimiting example, for clarity of description, suchreference to the AN may be understood as referring to a base station.However, those of ordinary skill in the art will comprehend that this ismay not always be the case, for example, as in certain 3G RANs wherebase stations are under the control or direction of centralized radionetwork controllers within their AN. In addition, both user plane (UP)and control plane (CP) functionality may be supported by the UE 202, theaccess networks 204 and 206 and the core networks 208 and 232. In FIGS.2-8, CP signaling is indicated by dashed lines, and UP signaling isindicated by solid lines.

In some examples, the legacy AN 204 may provide an access point to boththe legacy core network 232 and the next generation core network 208,while the next generation AN 206 may provide an access point to the nextgeneration core network 208. In other examples, the legacy AN 204 andthe next generation AN 206 may each provide respective access points toboth the legacy core network 232 and the next generation core network208.

In various aspects of the present disclosure, each access network(legacy AN 204 and next generation AN 206) may utilize a differentrespective radio access technology (RAT) to access a core network (e.g.,next generation core network 208 and/or legacy core network 232). Forexample, the legacy AN 204 may utilize a first (e.g., legacy) RAT toaccess a core network (e.g., either the next generation core network 208or the legacy core network 232), while the next generation AN 206 mayutilize a second (e.g., next generation) RAT to access a core network.

The legacy wireless AN 204 may be, for example, an Evolved UMTSTerrestrial Radio Access Network (E-UTRAN) within a Long Term Evolution(LTE) network, a Universal Mobile Telecommunications System (UMTS)Terrestrial Radio Access Network (UTRAN), a Wireless Local Area Network(WLAN) or other type of legacy access network. The next generationwireless AN 206 may be, for example, a 5G Radio Access Network (RAN) orEvolved E-UTRAN (i.e., an E-UTRAN enhanced to natively connect to thenext generation core network 208 with the same interface as the 5G RAN).In other examples, the next generation AN 206 may be a next generationWireless Local Area Network (WLAN), a next generation fixed broadbandInternet access network or other type of next generation access networkthat utilizes a next generation RAT to access the next generation corenetwork 208.

The legacy wireless AN 204 may include an evolved Node BS (eNB) 210 andother eNB's (not shown). The eNB 210 provides user and control planeprotocol terminations toward the UE 202. The eNB 210 may also bereferred to by those skilled in the art as a base station, a basetransceiver station, a radio base station, a radio transceiver, atransceiver function, a basic service set (BSS), an extended service set(ESS), or some other suitable terminology. The eNB 210 may be connectedto the other eNBs via an X2 interface (i.e., backhaul).

The eNB 210 provides an access point to the legacy core network 232,such as an Evolved Packet Core (EPC) network. In addition, although notshown, the next generation AN 206 may also provide an access point tothe legacy core network 232. The legacy core network 232 may include,for example, a Serving Gateway (SGW) 234, a Packet Data Network (PDN)Gateway 236 and a Mobility Management Entity (MME) 212. All user IPpackets are transferred through the SGW 234, which itself is connectedto the PDN Gateway 236. The PDN Gateway 236 provides UE IP addressallocation as well as other functions.

The MME 212 is the control node that processes the signaling between theUE 202 and the legacy core network 232. Generally, the MME 212 providesbearer and connection management for UEs 202 according to mechanismsdefined for the legacy core network 232. For example, the MME 212 maymanage security when a UE 202 connects to the legacy AN 206 by usinginformation provided by a Home Subscriber Server (HSS, not shown) toauthenticate UEs and update UEs location information in the HSS. The MME212 may further maintain the tracking area identity (TAI) of the currenttracking area (e.g., group of neighboring cells/eNBs) within which theUE 202 is located to enable paging of the UE 202 when the UE is in idlemode. In some examples, the legacy access network 204 may include asingle tracking area. In other examples, the legacy access network 204may include two or more tracking areas. Moreover, the MME 212 may manageconnectivity via Packet Data Connections (PDNs) between the UE 202 andthe PDN Gateway 236, and determine and provide a set of legacy Qualityof Service (QoS) parameters to the eNB 210.

In various aspects of the disclosure, the eNB 210 may further provide anaccess point to the next generation core network 208. In addition, thenext generation wireless AN 206 may also provide an access point to thenext generation core network 208. The next generation core network 208may include, for example, a control plane mobility management function(CP-MM) 216, a control plane session management function (CP-SM) 218, anevolved MME (eMME) 220, a user plane infrastructure 22, a user planegateway (UP-GW) 224, an evolved serving gateway (eSGW) 228 and a policyfunction 230. In some examples, the eMME 220 may be located outside ofthe next generation core network 208 (e.g., the eMME may be locatedwithin the legacy core network 232 or may be a stand-alone node). TheeMME 220 and eSGW 228 may be referred to herein as interworking corenetwork serving nodes, each configured to interwork between the legacycore network 232 and the next generation core network 208.

The CP-MM 216 provides mobility management and authentication of UEs102, while the CP-SM 218 processes signaling related to data networksessions involving UEs 202. For example, the CP-SM 218 may process datasession signaling from UEs 202 via a logical Next Generation-1 (NG-1)interface. The CP-MM 216 and CP-SM 218 may further be communicativelycoupled to the eMME 220 for interworking with the legacy core network232 and legacy AN 204 during deployment of next generation networks. Forexample, the eMME 220 may connect to the eNB 210 of the legacy AN 204via, for example, a logical S1 interface, to enable interworking of thecontrol plane with the legacy MME 212 via the eNB 210. The eNB 210within the legacy AN 206 may further be connected to the eSGW 228 withinthe next generation core network 208. The eSGW 228 provides interworkingof the user plane between the legacy AN 204 and the next generation corenetwork 208.

The next generation wireless AN 206 may include a control plane node 214for processing and handling control signaling within the next generationAN 206. The control plane node 214 is communicatively coupled to theCP-MM 216 and CP-SM 218 within the next generation core network 208 viarespective logical Next Generation-2 (NG-2) interfaces. The CP 214 mayfurther be communicatively coupled to the MME 212 within the legacy corenetwork 232 to provide signaling between the next generation AN 206 andthe legacy core network 232.

The UP infrastructure 222 facilitates routing of packet data units(PDUs) to and from UEs 202 via the next generation AN 206. PDU's mayinclude, for example, IP packets, Ethernet frames and other unstructureddata (i.e., Machine-Type Communication (MTC)).

The UP-GW 224 is connected to the UP infrastructure 222 to provideconnectivity to external data networks 226. In addition, the UP-GW 224may communicatively couple to the CP-SM 218 via, for example, a logicalNG-3 interface, to configure the UP connection over the next generationcore network 208. The UP-GW 224 may further connect to the eSGW 228within the next generation core network 208 to provide connectivitybetween the legacy AN 204 and the external data networks 226.

The UP-GW 224 further provides UE data connection address (e.g., IPaddress, Ethernet address and/or unstructured data identification)allocation and policy control. For example, the UP-GW 224 may becommunicatively coupled to a Policy Function 230 via, for example, alogical NG-4 interface, to determine network policies. The PolicyFunction 230 may further communicatively couple to the CP-SM 218 via,for example, a logical NG-5 interface, to provide policy information tothe CP-SM 218.

To establish a connection to the next generation (5G) core network 208via the next generation AN 206, the UE 202 may receive SystemInformation Blocks (SIBs) from the next generation AN 206 includinginformation regarding the capabilities of the AN 206, and upondetermining that the AN 206 is a next generation AN, transmit aconnectivity request (including an attach request) to the nextgeneration core network 208 via the next generation AN 206. Theconnectivity request may include a set of capabilities of the UE 202 tothe next generation core network (e.g., the CP-MM 216 and/or the CP-SM218). The set of capabilities may include, for example, an indicationthat the UE supports connectivity to legacy networks (e.g., legacy AN204). The set of capabilities may further include an indication ofwhether the UE supports inter-RAT handovers (e.g., a handover betweenthe next generation RAT and the legacy RAT in the access networks)initiated by the UE 202.

The CP-MM 216 and/or CP-SM 218 may process the connectivity requestbased on the set of capabilities, a UE profile, network policies andother factors. In various aspects of the disclosure, the CP-MM 216and/or CP-SM 218 may establish a data network session (DNS) connectionbetween the UE 202 and an external data network 226 over the nextgeneration AN 206 via the UP infrastructure 222. A DNS may include oneor more sessions (e.g., data sessions or data flows) and may be servedby multiple UP-GWs 224 (only one of which is shown for convenience).Examples of data flows include, but are not limited to, IP flows,Ethernet flows and unstructured data flows. Upon successfullyestablishing connectivity to the UE 202, the CP-MM 216 and/or CP-SM 218may further provide an indication of whether the next generation corenetwork 208 supports inter-RAT handovers initiated by the UE 202 and/ormay indicate whether the UE 202 is allowed to perform inter-RAThandovers.

The CP-MM 216 and/or CP-SM 218 may further use one or more of the set ofcapabilities, a UE profile, network policies, and other factors toselect a Quality of Service (QoS) to be associated with the connectivityto the UE 202. For example, if the set of capabilities indicates thatthe UE 202 supports connectivity to legacy networks 204, and includessome of the QoS parameters used in legacy networks (e.g., Guaranteed BitRate (GBR) and/or specific QoS Class Identifiers (CQIs)), the QoS mayinclude one or more QoS parameters associated with the next generationcore network 208 and one or more QoS parameters associated with thelegacy AN 204 to enable interworking with the legacy network 204 in caseof handover from the next generation AN 206 to the legacy AN 204. Thus,the CP-MM 216 and/or CP-SM 218 may establish values for 5G QoSparameters and values for legacy QoS parameters. These parameters may bestored in the CP-MM and/or the CP-SM upon connectivity establishment tothe next generation core network 208 and provided to the eMME 220 uponhandover to the legacy AN 204.

However, if the next generation AN 206 is a non-3GPP AN (e.g., a WLANAccess Point, WiFi Access Point, etc.), the non-3GPP AN may provide innon-access stratum (NAS) messages (e.g., higher level signalingmessages) a set of information on the core network capabilities,including an indication of whether the core network is a next generationcore network 208. Based on the indication that the core network is anext generation core network 208, the UE 202 may provide the set ofcapabilities of the UE, described above. In other examples, the UE mayquery the non-3GPP AN for the Access Point (AP) capabilities (includingsupported core network capabilities) prior to connectivity, using, forexample, a HotSpot 2.0 policy query response mechanism. The non-3GPP ANmay respond to the query with the core network capabilities, includingan indication of whether the core network is a next generation network.For example, a HotSpot 2.0 management object may be enhanced to includean indication of whether the core network is a next generation network.

To establish a connection to the next generation (5G) core network 208via the legacy (3G or 4G) AN 204, the UE may provide a connectivityrequest message to the MME 212 selected by the legacy AN 204. In someexamples, the connectivity request message may be a NAS messageincluding a UEAccessCapabilities Information Element that provides theset of capabilities of the UE 202. For example, the set of capabilitiesmay include an indication that the UE supports connectivity to nextgeneration networks (e.g., next generation CN 208) and an indication ofwhether the UE supports inter-RAT handovers (e.g., a handover betweenthe legacy RAT and the next generation RAT) initiated by the UE 202. Insome examples, the NAS message may be encapsulated in an Access Stratum(AS) message, and both the NAS message and the AS message may include anindication of whether the UE supports connectivity to next generationnetworks.

Based on the set of capabilities, the MME 212 may transfer theconnectivity request to an eMME 220. For example, if the set ofcapabilities indicates that the UE supports connectivity to nextgeneration networks, the MME 212 may transfer the connectivity requestto the eMME 220 serving the current tracking area of the UE 202 that isassociated with the legacy AN 204. In some examples, the MME 212 may beconfigured with a list of eMMEs serving the current tracking area of theUE 202 associated with the legacy AN 204 and may select one of the eMMEsfrom the list for redirection of the connectivity request. The list ofeMMEs may be included, for example, in one or more configuration tablesin the MME 212. The configuration tables may be configured, for example,by the network operator. In some examples, the MME 212 may forward theconnectivity request to the eMME 220. In other examples, the MME 212 mayredirect the connectivity request from the eNB 210 to the eMME 220 viathe eSGW 228 (e.g., the MME 212 may instruct the eNB 210 to send theconnectivity request to the eMME 220).

The eMME 220 may process the connectivity request based on the set ofcapabilities, a UE profile, network policies and other factors. The eMME220 may further use one or more of the set of capabilities, a UEprofile, network policies, and other factors to select a Quality ofService (QoS) to be associated with the connectivity to the UE 202. Insome examples, the eMME 220 may establish values for 5G QoS parametersand values for legacy QoS parameters. Upon successfully establishingconnectivity to the UE 202, the eMME 220 may further provide anindication of whether the next generation core network 208 supportsinter-RAT handovers initiated by the UE 202 via the eSGW 228.

In one example, when the UE 202 attaches to the legacy AN 204, the eMME220 acts as a CP-MM 216 to anchor the MM context. In this example, theUE 202 establishes an enhanced mobile management (EMM) context with theeMME 220 and authenticates with the eMME 220 using legacy mechanisms.The eMME 220 may interact with an Authentication, Authorization andAccounting (AAA) server/HSS (not shown) to retrieve the subscriberprofile for the UE and perform authentication and key derivation tosecure the radio link Upon handover to a next generation AN 208, theeMME 220 may then interact with a CP-MM 216 (selected during thehandover procedure based on the identity of the target cell or nextgeneration AN), and the MM context may be transferred from the eMME 220to the target CP-MM 216.

In another example, when the UE 202 attaches to the legacy AN 204, aCP-MM 216 may be used to anchor the MM context. In this example, the UEestablishes an EMM context with the eMME 220. The eMME 220 may thenselect a serving CP-MM 216 based on preconfigured information (e.g.,based on the location of the serving legacy cell), and trigger an MMcontext establishment towards the CP-MM 216. The CP-MM 216 may performUE authentication with message exchanges between the UE 202 and CP-MM216 routed via the eMME 220. Thus, the CP-MM 216 may interact with theAAA/HSS to retrieve the subscriber profile and perform theauthentication and key derivation to secure the radio link.

In some examples, the CP-MM 216 may further receive a set of keys fromthe AAA/HSS for the next generation core network, derive a set of keysspecific to the legacy AN, and distribute the legacy keys to the eMME220 to secure the radio link In other examples, the CP-MM 216 maydistribute the next generation keys received from interaction with theAAA/HSS to the eMME 220, and the eMME 220 may then map the nextgeneration keys to legacy keys (e.g., keys suitable for the legacy AN).As a result, two MM contexts are created and maintained: one in the eMME220 and one in the CP-MM 216. However, for UE mobility within the legacyAN 204, the eMME 220 may not interact with the CP-MM 216 unless a changeof eMME (e.g., from a source eMME to a target eMME) is triggered by theUE mobility, in which case the eMME (either source or target) may informthe CP-MM 216 of the change in eMME. Upon handover to a next generationAN 206, the serving CP-MM 216 may continue to serve the UE attached tothe next generation AN 206, or a CP-MM relocation to a target CP-MM mayoccur based on the location of the UE, in which case the MM context ismoved to the target CP-MM.

FIG. 3 is a block diagram illustrating an initial connectivity of a UE202 to a next generation core network 208 over a legacy AN 204. In theexample shown in FIG. 3, the UE 202 may first establish connectivity toa legacy core network 232 through the legacy wireless AN 204 utilizing alegacy RAT. The MME 212 in the legacy core network 232 receives theconnectivity request, which may be, for example, a non-access stratum(NAS) message, including a set of capabilities of the UE. The set ofcapabilities may include, for example, an indication of whether the UEsupports legacy and/or next generation RATs and an indication of whetherthe UE supports an inter-RAT handover (i.e., between legacy and nextgeneration ANs) initiated by the UE.

Based on the set of capabilities and/or a user profile/subscription, theMME 212 may determine that the UE supports a next generation RAT andselect an interworking core network serving node (e.g., eMME 220) toestablish and relocate connectivity of the UE 202 to the next generationcore network 208. For example, the MME 212 may access a configurationtable 300 configured by the operator that maintains a list of eMMEs andselect the eMME 220 that serves a current tracking area of the UE 202associated with the legacy wireless AN 204. The MME 212 may furthertransfer the NAS message to the selected eMME 220 (e.g., the MME 212 mayeither forward the NAS message to the eMME 220 or redirect the NASmessage to the eMME 220 via the legacy AN 204 and the eSGW 228).

Since the legacy AN 204 may not support DNS connections, to establishdata connectivity to the next generation core network 208 and provideinterworking via the legacy AN 204, aspects of the disclosure enable theeMME 220 to establish a packet data network (PDN) connection 302 overthe legacy AN 204 between the UE 202 and a UP-GW 224 via the nextgeneration core network 208. During the PDN connection establishment,the eMME 220 may act as a CP-SM or the CP-SM 218 may be involved toanchor the SM context. If the eMME 220 acts as a CP-SM, the UE 202 mayestablish an enhanced session management (ESM) context with the eMMEusing legacy mechanisms. In this example, the SM context may only becreated in the eMME 220. The eMME 220 may then perform SM functionalitybased on the connectivity parameters provided by the UE 202. Such SMfunctionality may include, for example, UP-GW 224 selection, tunnelestablishment between the UP-GW 224 and eSGW 228, etc.

If the CP-SM 218 is involved to anchor the SM context, upon receivingthe PDN connectivity request from the UE 202, the eMME 220 may select aCP-SM 218 based on preconfigured information (e.g., the location of theserving legacy cell) and forward the connectivity request to the CP-SM218, including all of the parameters provided by the UE 202. The SMfunctionality may then be performed by the CP-SM. In either of the abovescenarios, a single UP-GW 224 may be selected to serve the PDNconnection 302, and a single data connection address (e.g., IPv4 and/orIPv6, or other type of address, such as Ethernet or unstructured dataidentification) may be provided to the UE 202 for the PDN connection302.

If multiple data connection addresses are required for connectivity to aparticular external data network, in one example, the UE 202 may requestadditional data connection addresses upon handover to a next generationAN 206. In another example, when a PDN connection is established overthe legacy AN 204, the next generation core network may return to the UE202 an indication of whether multiple data connection addresses can besupported over the PDN connection, and provide a set of information tobe used by the UE 202 to request additional data connection addresses.The set of information may include, for example, an addresscorresponding to the serving UP-GW 224 that enables the UE to requestadditional data connection addresses from the UP-GW 224. The UE 202 maythen request additional data connection addresses using a protocol, suchas Dynamic Host Configuration Protocol (DHCP), where the UP-GW 224 actsas a DHCP server and selects an additional data connection address. TheUP-GW 224 may further interact with the eMME 220 or the CP-SM 218 toauthorize the request.

In another example, if multiple data connection addresses are required,when a PDN connection is established over the legacy AN 204, the nextgeneration core network may return to the UE 202 an indication ofwhether multiple data connection addresses can be supported over thenext generation core network. The UE 202 may then use enhanced NASsignaling to the eMME 220 to request additional data connectionaddresses and provide the connectivity requirements for the new dataconnection addresses (e.g., the type of session continuity required).Upon receiving the request, the eMME 220 may either evaluate the requestor forward the request to the serving CP-SM 218. The eMME 220 or theCP-SM 218 may then verify that the UE is authorized to request a newdata connection address and process the information provided by the UE.The eMME 220/CP-SM 218 may then select a UP-GW 224, which assigns thenew data connection address, and establishes the connectivity to theUP-GW 224, including, for example, tunnel establishment between the newUP-GW 224 and the eSGW 228. The eMME 220/CP-SM 218 may then return thenew data connection address to the UE 202.

In some examples, different credentials may be desired for different PDNconnections. To enable enhanced session management (ESM) based ondifferent credentials than the one used to establish an enhancedmobility management (EMM) context with the eMME 220, NAS ESM signalingmay be further enhanced to enable the PDN connection procedure to allowan authorization separate from the authorization used for the EMMestablishment based on a set of credentials provided by the UE 202. Inthis example, a NAS signaling exchange may be introduced to encapsulatean authentication protocol exchange (e.g., EAP) between the UE 202 andthe entity performing the authentication (e.g., the eMME 220 or theCP-SM 218, depending on where the SM context is anchored).

If the eMME 220 performs the authentication, the eMME 220 may interactwith the AAA/HSS (identified based on the credentials provided by theUE) to retrieve the subscriber profile and perform the authenticationsand key derivation to secure over the radio link one or more of thesignaling and PDUs corresponding to the ESM context being authenticated.Upon handover to a next generation AN 206, the eMME 220 may interactwith the CP-SM 218 (selected during the handover procedure based on,e.g., one or more of the identity of the target AN, location of thetarget AN, service and/or connectivity requirements provided by the UEor derived from the UE profile during connectivity establishment, etc.),and the SM context may be transferred from the eMME 220 to the CP-SM218.

If the CP-SM 218 performs the authentication, the CP-SM 218 may interactwith the AAA/HSS (identified based on the credentials provided by theUE) to retrieve the subscriber profile and perform the authenticationsand key derivation to secure over the radio link one or more of thesignaling and PDUs corresponding to the ESM context being authenticated.For example, the CP-SM 218 may derive a set of keys specific to legacynetworks and distribute the legacy keys to the eMME 220 or the CP-SM 218may distribute the derived keys to the eMME 220 and the eMME 220 maythen map the derived keys to legacy keys. In this example, two SMcontexts may be created and maintained: one in the eMME 220 and one inthe CP-SM 218. Upon handover to a next generation AN 206, the CP-SM 218may distribute the existing keys for the ESM context to the target AN ormay derive new keys. In addition, the serving CP-SM 218 may continue toserve the UE attached to the new next generation AN 206, or a CP-SMrelocation may occur. If a CP-SM relocation occurs, the SM context maybe transferred to the new/target CP-SM.

When a UE 202 establishes a PDN over a legacy AN 204, if the UE 202provides an Access Point Name (APN) or an APN is selected by the eMME220, and the UE is not enabled to provide connectivity requirements orthe UE does not provide them, in one example, the eMME 220 may interactwith the AAA/HSS and/or a CP-SM 218 (selected by the eMME 220 based onpreconfigured information) to derive the connectivity requirementscorresponding to the APN that would apply for equivalent connectivityover a next generation AN 206. In another example, the eMME 220 may bepreconfigured to map a specific APN to specific connectivityrequirements. If the eMME 220 is acting as a CP-SM, the eMME 220 may usethe connectivity requirements for connectivity establishment (e.g., QoSestablishment, UP-GW selection, etc.). If the CP-SM 218 is involved toanchor the SM context, the eMME may forward the connectivityrequirements to the CP-SM 218 for connectivity establishment.

FIG. 4 is a block diagram illustrating an initial connectivity of a UE202 to a next generation core network 208 over a next generation (e.g.,5G) AN 206. In the example shown in FIG. 4, the UE 202 may attempt toestablish connectivity to a next generation core network 208 through anext generation AN 206. For example, the UE 202 may transmit aconnectivity request including a set of capabilities of the UE 202 tothe next generation core network 208 via the next generation AN 206 andthe CP 214. The set of capabilities may include, for example, anindication of whether the UE supports legacy and/or next generation RATsand an indication of whether the UE supports an inter-RAT handover(i.e., between legacy and next generation ANs) initiated by the UE.

The connectivity request may be received, for example, by a CP-SM 218and/or CP-MM 216 within the next generation core network 208. Upondetermining that the UE 202 supports the next generation RAT, the CP-SM218 and/or CP-MM 216 processes the connectivity request to establishdata connectivity between the UE 202 and the next generation corenetwork 208. For example, the CP-SM 218 and/or CP-MM may establish adata network session (DNS) connection between the UE 202 and an externaldata network over the next generation AN 206 via the UP infrastructure222. A DNS may include one or more sessions (e.g., data sessions or dataflows) and may be served by multiple UP-GWs 224 (only one of which isshown for convenience). Examples of data flows include, but are notlimited to, IP flows, Ethernet flows and unstructured data flows.

During the DNS connection establishment, for example, the CP-SM 218 mayestablish an enhanced session management (ESM) context for the UE 202.The CP-SM 218 may then perform SM functionality based on theconnectivity parameters provided by the UE 202. Such SM functionalitymay include, for example, connection establishment via the UPinfrastructure 222. For example, to establish the DNS, a set of contextinformation may be provided in various entities within the UPinfrastructure 222 of the next generation core network 208 to provideconnectivity between the UE 202 and an external data network (e.g., IMS,Internet or other dedicated data networks). In various aspects of thepresent disclosure, the UP-GW 224 may further support multiple datanetwork sessions between a single UE 202 and one or more external datanetworks 226.

FIG. 5 is a block diagram illustrating one example of communicationutilizing multiple data network sessions between a UE 202 and one ormore external data networks 226. In the example shown in FIG. 5, the UE202 is actively engaged in two data network sessions (DN Session 1, 226a and DN Session 2, 226 b). Each data network session (DNS) is a logicalcontext in the UE 202 that enables communication between a localendpoint in the UE (e.g., a web browser) and a remote endpoint (e.g. aweb server in a remote host) and each DNS connection may include one ormore data sessions (e.g., IP, Ethernet and/or unstructured datasessions). In the example shown in FIG. 5, DN Session 1 is served byUP-GW 224 a and includes two IP sessions (IP1 and IP2), each associatedwith a different IP address of the UE 202. DN Session 2 also includestwo IP sessions (IP3 and IP4), each associated with a different IPaddress of the UE 202. However, IP3 is served by UP-GW 224 b, while IP4is served by a local UP-GW 224 c. The session management context (e.g.,leveraging software defined networking (SDN) and signaling routing) forDN Session 1 and DN session 2 is provided in the CP-SM 218. The userplane context (e.g., Quality of Service (QoS), tunneling, etc.) for DNSession 1 is provided in the UP-GW 224 a, while the user plane contextfor DN Session 2 is provided in both UP-GW 224 b and local UP-GW 224 c.

FIG. 6 illustrates another example of a UE 202 engaged in multiple DNSessions 600 a-600 c over a next generation AN 206. Each DN Session 600a-600 c includes one or more IP sessions (IP flows) 610 a-610 e, andeach IP flow 610 a-610 e is associated with a respective IP address forthe UE 202. For example, DN Session 600 a includes IP flow 610 a, whichis served by UP-GW 224 a and provides connectivity between the UE 202and a first external data network 226 a (DN1). DN Session 600 b includesIP flows 610 b and 610 c, which are served by UP-GW 224 b and provideconnectivity between the UE 202 and the first external data network 226a (DN1). DN Session 600 c includes IP flows 610 d and 610 e, which areserved by UP-GW 224 c and provide connectivity between the UE 202 andthe second external data network 226 b (DN2).

If the UE 202 roams into an area (tracking area/cell) served by a legacyAN 204, traffic may need to be handed off from the next generation AN tothe legacy AN. However, legacy ANs typically support only one IP addressfor each UE. Therefore, to support multiple DN sessions and multiple IPaddresses in legacy networks, IP sessions (IP flows) in next generationnetworks may be mapped to Packet Data Network (PDN) connections inlegacy ANs. To support multiple IP addresses per PDN connection, the UE202 and eMME 220 enhanced session management (ESM) contexts may each bemodified, as described below.

Referring now to FIG. 7, the DN Sessions and IP flows shown in FIG. 6have each been handed over from the next generation AN 206 to the legacyAN 204. In the example shown in FIG. 7, each IP flow 610 a-610 e hasbeen mapped to one of two PDN connections (PDN1 and PDN2). Each PDNconnection PDN1 and PDN2 in the legacy AN 204 is an association betweenthe UE 202 and a packet data network 226 (external DN1 or external DN2).

The eMME 220 maps the IP flows 610 a-610 e to PDN connections. Invarious aspects of the present disclosure, the eMME 220 may map each IPflow 610 a-610 e to a PDN connection (PDN1 or PDN2) based on at leastthe external data network associated with the IP flow 610 a-610 e. Forexample, IP flows 610 a-610 c may be mapped to PDN1 and IP flows 610d-610 e may be mapped to PDN2 in the eMME 220. In some examples, thecharacteristics of the IP flows 610 a-610 e (e.g., QoS, packetprocessing requirements, etc.) may further be used to map IP flows 610a-610 e to PDN connections. In this example, more than one PDNconnection may be utilized to provide connectivity between the UE 202and a particular external data network to accommodate different IP flowcharacteristics.

To facilitate handover of multiple DN Sessions and IP flows, theenhanced session management (ESM) context of the eMME 220 may bemodified to support multiple IP addresses on a single PDN connection.Each PDN connection (PDN1 and PDN2) may utilize a Generic TunnelingProtocol (GTP) tunnel on the S1 interface to transmit traffic betweenthe legacy AN 204 and the eSGW 228. In addition, each PDN connection maybe represented by a single IP address (IPv4 and/or IPv6) in the legacyAN 204 (e.g., a single IP address may be used for the PDN connectionbetween the UE 202 and the eSGW 228 via the eNB). Thus, PDUs from eachIP flow (each having a different IP address) may be encapsulated intoPDN PDU's (having the same IP address) for routing over the tunnels.

The eMME 220 provides the mapping to the eSGW 228 to enable the eSGW 228to map IP flows received on the downlink from UP-GWs 224 a-224 c to thecorresponding GTP tunnels to the legacy AN 204. On the uplink, PDU'sreceived by the eSGW 228 on PDN1 and PDN2 are mapped to the appropriateIP flows and routed to the appropriate UP-GWs 224 a-224 c based onrouting information provided by the CP-SM 218. The UE 202 may further beconfigured with the IP flow-PDN connection mapping to enable the UE 202to place PDUs on the appropriate PDN connections (e.g., the ESM contextin the UE may be modified to map PDUs to PDN connections). For example,the UE 202 may encapsulate IP flow PDU's into PDN PDU's for routing overthe appropriate tunnels. The eSGW 228 may decapsulate the PDN PDU's toretrieve the IP flows 610 a-610 e for routing to the appropriate UP-GWs224 a-224 c.

FIG. 8 illustrates another exemplary model for interworking betweenlegacy ANs and next generation core networks after handover from a nextgeneration AN 206 to a legacy AN 204. In the example shown in FIG. 8,GTP tunnels 900 a-900 c may also created between the eSGW 228 and theUP-GW 224 a-224 c, corresponding to the GTP tunnels within the PDNconnections (PDN1 and PDN2). However, if a set of IP flows mapped on aparticular PDN connection between the eSGW 228 and the legacy AN 204 isserved in the next generation core network 208 by multiple UP-GWs 224,the PDN connection in the next generation core network may be mapped tomultiple tunnels from the eSGW 228 to the UP-GWs, corresponding to theactual PDN between the UE 202 and the eSGW 228. For example, PDN1 may bemapped to two tunnels 900 a and 900 b to route the IP flows to theappropriate UP-GWs 224 a and 224 b. PDN2 may be mapped to a singletunnel 900 c, since all of the IP flows within PDN2 are served by thesame UP-GW 224 c.

In some examples, the tunnels may be established by the eMME 220interacting with the CP-SM 218 to provide tunneling information to theeSGW 228 (via the eMME 220) and UP-GWs 224 a-224 c (via the CP-SM 218).For example, the eSGW 228 on the UL may map the UL PDUs to the correcttunnel 600 a-600 c to ensure delivery to the correct UP-GW 224 a-224 c.To do so, when the handover takes place, the eMME 220, based oninformation from the CP-SM 218 and/or CP-MM 216, may configure the eSGW228 with mapping information between UL IP flows and the tunnels 900a-900 c from the eSGW 228 to the UP-GWs 224 a-224 c. The eSGW 228 mayfurther be configured to correctly map PDUs from the tunnels 900 a-900 cfrom one or more UP-GWs 224 a-224 c to the correct PDN connection (PDN1or PDN2) between the eSGW 228 and the legacy eNB.

In some examples, either the CP-MM 216/CP-SM 218 or the next generationAN 206 may control the handover. If the CP-MM 216/CP-SM 218 controls thehandover, in one example, the next generation AN 206 may provide theidentity of a target cell in the legacy AN 204 to the CP-MM 216 and/orCP-SM 218. The CP-MM 216 and/or CP-SM 218 may then select a target eMME220 based on the target cell identity (e.g., the CP-MM 216 and/or CP-SM218 may be configured with a mapping between a target cell ID and thecorresponding eMME 220, at least for target cells neighboring the nextgeneration AN 206). In this example, the CP-MM 216 and/or CP-SM 218 haveawareness of the legacy/next generation AN 204/206 technologies and thetopology of the access networks.

In other examples, when the CP-MM 216/CP-SM 218 controls the handover,the next generation AN 206 may select the target eMME 220 based on theidentity of the target cell (i.e., next generation ANs 206 areconfigured with a mapping between the target cell ID and thecorresponding eMME 220, at least for target cells neighboring the nextgeneration AN 206). The next generation AN 206 may then trigger thehandover to the CP-MM 216 and/or CP-SM 218. In this example, the CP-MM216 and/or CP-SM 218 may not have awareness of the legacy/nextgeneration AN 204/206 technologies and the topology of the accessnetworks.

However, if the next generation AN 206 controls the handover, the nextgeneration AN 206 may select the target eMME 220 based on the identityof the target cell (i.e., next generation ANs 206 may be configured witha mapping between the target cell ID and the corresponding eMME 220, atleast for target cells neighboring the next generation AN 206). Thetarget eMME 220 may then interact with the serving CP-MM 216 and CP-SM218 to authorize the handover and establish or modify the networkconnectivity (e.g., tunnels).

If the UE 202 is capable of connecting to both the next generation AN206 and the legacy AN 204 simultaneously and perform a make before breakhandover, the UE 202 may initiate the handover by connecting to thelegacy AN 204, attaching to the next generation core network 208(possibly with an indication a handover is being performed), andestablishing PDN connectivity (possibly with an indication a handover isbeing performed). The eMME 220 selected to serve the UE 202 by theMME/eNB (shown in FIG. 2) may then interact with the serving CP-MM 216and/or serving CP-SM 218 to retrieve the UE context. The eMME 220 maydiscover the serving CP-MM 216 and/or serving CP-SM 218, for example,based on identifiers provided by the UE in the connectivity/attachrequest. In some examples, the eMME 220 translates the identifiersprovided by the UE into the addresses of the CP-MM 216 and/or CP-SM 218.

In any of the above scenarios, the eMME 220 may appear to the CP-MM216/CP-SM 218 as either another next generation AN or as another CP-MM216/CP-SM 218. If the eMME 220 appears as another next generationnetwork, the interface between the eMME 220 and the CP-MM 216/CP-SM 218may be the same as the interface between the CP-MM 216/CP-SM 218 and thenext generation AN 206. In examples in which the CP-MM 216 and/or CP-SM218 controls the handover, upon receiving a handover trigger from thenext generation AN 206 (e.g., source AN), the CP-MM 216 and/or CP-SM 218may perform the handover to the eMME 220 (e.g., target AN). Whenconnectivity is established for the handover, the CP-MM 216 and/or CP-SM218 may address the eMME 220 the same as if the handover were performedbetween two next generation ANs. In examples in which the nextgeneration AN controls the handover, the source AN 206 may trigger thehandover to the target AN (eMME 220), and either AN (source or target)may interact with the serving CP-MM 216 and/or CP-SM 218 to perform thehandover. However, if the eMME 220 appears as another CP-MM 216 and/orCP-SM 218, handover and connectivity establishment procedures may beperformed the same as a handover between two next generation networksthat require CP-MM 216 and/or CP-SM 218 relocation.

In addition, in any of the above scenarios, if the eMME 220 acts as ananchor for the MM and SM context, after the handover, the previouslyserving CP-MM 216 and CP-SM 218 may be released and both the MM and SMcontexts may be anchored in the eMME 220. However, if the context isanchored in a CP-MM 216 and/or CP-SM 218, the serving CP-MM 216 and/orCP-SM 218 may continue to serve the UE 202 while connected to the legacycell, with control signaling between the UE 202 and the CP-SM 218 andCP-MM 216 routed via the eMME 220.

Although all IP flows 610 a-610 e in FIGS. 7 and 8 were handed over fromthe next generation AN 206 to the legacy AN 204, in some examples, notall IP flows may be transferrable to legacy ANs. The CP-MM 216 and/orCP-SM 218 may determine whether or not each IP flow 610 a-610 e istransferrable to the legacy AN 204 based on, for example, localconfiguration by the operator, the UE subscription profile (which maycontain restrictions on the transferability of certain types of IPflows), an indication by the UE when the data connectivity (for an IPflow or a set of IP flows) is established, and other factors. For the IPflows 610 a-610 e that are transferrable, the CP-MM 216 and/or CP-SM 218provides the QoS parameters for the transferred IP flows to the eMME220. The QoS parameters may include next generation QoS parameters andlegacy QoS parameters, as described above.

In next generation core networks, traffic (i.e., PDUs) may be labeledwith tokens (one for the uplink (UL) and/or one for the downlink (DL))for traffic differentiation. For example, an UL token may be generatedby the core network, and delivered to the UE for uplink traffic. The ULtoken may be consumed by the UP-GW 224 for traffic verification. The ULtoken may further be consumed by the next generation AN 206 for trafficverification and filtering. A DL token may be generated in conjunctionwith an application server that generates DL traffic, and is deliveredto the application server. The DL token may be further consumed by theUP-GW 224 for DL traffic verification and filtering (i.e., to verify ifthe traffic is authorized and what policies should be applied, includingQoS). The DL token may further be consumed by the next generation AN 206to enable matching between the PDU and the AN resources needed totransport the PDU over the access link.

To provide interworking with legacy ANs for tokens, the UL and DL tokensmay be delivered by the next generation core network to the eMME 220 andeSGW 228 and used in the same way before mapping to PDN connections. Inorder to deliver the tokens to the UE over the legacy AN, NAS signalingover the legacy AN may be enhanced to carry the tokens. In someexamples, the legacy AN (eNB) may not process the tokens, but insteadmerely forward the tokens without processing. If the UE 202 receives theUL token when connected to the legacy AN 204, the UE 202 may apply thetoken (i.e., insert it) in all PDU's corresponding to the IP dataflow(s) the token is associated with.

In either FIG. 7 or FIG. 8, the handover from the next generation AN 206to the legacy AN 204 may be initiated by the next generation AN 206 orby the UE 202. If the next generation AN 206 initiates the handover, ahandover trigger is provided by the next generation AN 206 to the eMME220. For example, referring now to the signaling diagram of FIG. 9, at902, the next generation AN 206 may receive measurement information fromthe UE, including measurements for legacy cells. From the measurementinformation, at 904, the next generation AN 206 may determine that ahandover is needed and select the target cell (i.e., a legacy cell). At906, the next generation AN triggers the handover towards a core networkserving node 900 (CP-MM and/or CP-SN) and provides a descriptor of nextgeneration AN resources (e.g., configuration of radio bearers, securityinformation, etc.).

If the target cell is a legacy cell, the next generation AN 206 mayselect the eMME 220 based on the target cell ID and provide the identityof the eMME 220 to the core network serving node 900 or the core networkserving node 900 may select the eMME based on the target cell ID, asshown at 908. At 910, the core network serving node 900 may forward thehandover request to the eMME 220. The eMME 220 may process the handoverrequest or, as shown at 912 in FIG. 9, identify an MME 212 forprocessing the handover request based on the target cell ID. If the eMME220 selects an MME 212 for processing the handover request, at 914, theeMME 220 may then forward the handover request to the MME 212. Eitherthe MME 212 or the eMME 220 (e.g., if the eMME continues to serve the UE202 in the target legacy cell) may then forward the handover request tothe target eNB 210. The eMME 220 may further convert the next generationAN resources information into legacy access information and, if the eMME220 selected an MME 212, provide the legacy access information to theMME. The next generation AN 206 or the core network serving node 900 mayfurther provide to the MME 212 legacy specific QoS parametersestablished when the QoS was established in the next generation AN 206.When the handover is successfully completed, at 918 and 920, aconfirmation message is returned by the eNB 210 to the MME 212 and eMME220, which forwards the confirmation to the core network serving node900 at 922. The core network serving node 900 may then forward theconfirmation to the next generation AN 206 at 924, which provides ahandover command to the UE 202 at 926.

For a handover from a legacy cell (legacy AN 204) to a next generationAN 206, the handover may be initiated by the legacy AN 204 or by the UE202. If the legacy AN 204 initiates the handover, a handover trigger isprovided by the legacy AN 204 to the eMME 220. For example, referringnow to the signaling diagram of FIG. 10, at 1002, the eNB 210 mayreceive measurement information from the UE, including measurements fornext generation AN cells. From the measurement information, at 1004, theeNB 210 may determine that a handover is needed and select the targetcell. If the target cell is a next generation cell, the eNB 210 triggersthe handover towards the eMME 220, including the information exchangedbetween the legacy eNB and next generation eNB 210 for inter-eNBhandover (e.g., configuration of radio bearers, security information,etc.). The eNB 210 may be configured with the address of the eMME 220,as shown at 1010, or the eNB 210 may forward the handover request to theMME 212, which is configured to detect that the target cell is a nextgeneration cell and to select a corresponding eMME 220 for the handover,as shown at 1006. The MME 212 may then either redirect the eNB 210 tosend the handover request to the eMME 220, as shown at 1008 and 1010, orforward the handover request to the eMME (as in an inter-MME handover),as shown at 1012. In some examples, the MME 212 may be configured as aneMME, in which case, redirection to the eMME 220 is not necessary.

The eMME 220 (or MME 212) uses the target cell ID to select a corenetwork serving node 900 (CP-SM and/or CP-MM) at 1014. The eMME 220 (orMME 212) may further convert the information provided by the eNB 210(e.g., configuration of radio bearers) into next generationconfiguration information for the target next generation AN, and forwardthe handover request containing the converted information to the corenetwork serving node 900 at 1016. The core network serving node thenselects the next generation AN corresponding to the target cell ID andcontinues the handover preparation at 1018. When the handover issuccessfully completed, at 1020, a confirmation message is returned bythe target next generation AN to the core network serving node 900,which forwards the confirmation to the eMME 220 at 1022. The eMME 220may then forward the confirmation to either the MME 212 at 1024 or theeNB 210 at 1026, which provides a handover command to the UE 202 at1028.

In some examples, if the eMME 220 is acting as a CP-MM 216 and/or CP-SM218, for CP-MM 216 and/or CP-SM 218 controlled handovers, the eMME 220selects a target CP-MM 216 and/or CP-SM 218 based on the identity of thetarget cell. For example, the eMME 220 may be configured with a mappingbetween a target cell ID and the corresponding CP-MM and/or CP-SM, atleast for target cells neighboring the legacy AN 204. The eMME 220 maythen forward the handover request to the target CP-MM and/or CP-SM. Fora legacy AN controlled handover, the eMME 220 may select the target nextgeneration AN 206 based on the identity of the target cell (e.g., theeMME may be configured with a mapping between the target cell ID and thecorresponding next generation AN, at least for target ANs neighboringthe source legacy cell), and trigger the handover to the target nextgeneration AN. The target next generation AN may then interact with aCP-MM and/or CP-SM to establish the connectivity and context. If a CP-SMis an anchor for the SM context, the eMME 220 forwards the handoverrequest to the current CP-MM and/or CP-SM to establish the connectivitywith the target next generation AN.

As discussed above, when the legacy AN 204 triggers the handover to anext generation AN, the eNB may forward the handover signaling to theeMME 220. To enable forwarding of the handover signaling to the eMME220, the identifiers of the target cells should map to an area thatrequires the eMME 220 for the handover signaling. Thus, when assigningcell identifiers to next generation AN cells that overlap with legacycells, in some examples, the identifiers of the next generation cellsmay correspond to a different coverage area (e.g., tracking area orzone) than the legacy cells.

If the UE 202 is capable of connecting to both the next generation AN206 and the legacy AN 204 simultaneously and perform a make before breakhandover, the UE 202 may initiate the handover by connecting to the nextgeneration AN 206, attaching to the next generation core network 208(possibly with an indication a handover is being performed), andestablishing connectivity (possibly with an indication a handover isbeing performed). The CP-MM 216 and CP-SM 218 selected to serve the UE202 may interact with the serving eMME 220 to retrieve the UE context.If the context was anchored in a CP-MM and/or CP-SM, a new serving CP-MMand/or serving CP-SM may not be selected, and the existing CP-MM and/orCP-SM may be selected by the next generation core network based onidentifiers provided by the UE in the connectivity/attach request or bytranslating the identifiers into the addresses of the existing CP-MMand/or CP-SM. In any of the above scenarios, after the handover from thelegacy AN 204 to the next generation AN 206, the context in the eMME 220and eSGW 228 is released.

FIG. 11 is a conceptual diagram illustrating an example of a hardwareimplementation for a core network serving node 1100 employing aprocessing system 1114. In accordance with various aspects of thedisclosure, an element, or any portion of an element, or any combinationof elements may be implemented with a processing system 1114 thatincludes one or more processors 1204. The core network serving node 1100may correspond to, for example, the MME, CP-MM, CP-SM, eMME or eSGW.

Examples of processors 1104 include microprocessors, microcontrollers,digital signal processors (DSPs), field programmable gate arrays(FPGAs), programmable logic devices (PLDs), state machines, gated logic,discrete hardware circuits, and other suitable hardware configured toperform the various functionality described throughout this disclosure.That is, the processor 1104, as utilized in the core network servingnode 1100, may be used to implement any one or more of the processesdescribed below.

In this example, the processing system 1114 may be implemented with abus architecture, represented generally by the bus 1102. The bus 1102may include any number of interconnecting buses and bridges depending onthe specific application of the processing system 1114 and the overalldesign constraints. The bus 1102 links together various circuitsincluding one or more processors (represented generally by the processor1104), a memory 1105, and computer-readable media (represented generallyby the computer-readable medium 1106). The bus 1102 may also linkvarious other circuits such as timing sources, peripherals, voltageregulators, and power management circuits, which are well known in theart, and therefore, will not be described any further. A bus interface1108 provides an interface between the bus 1102 and a network interface1110. The network interface 1110 provides a means for communicating withvarious other apparatus over a transmission medium. Depending upon thenature of the apparatus, a user interface 1112 (e.g., keypad, display,touch screen, speaker, microphone, joystick) may also be provided.

The processor 1104 is responsible for managing the bus 1202 and generalprocessing, including the execution of software stored on thecomputer-readable medium 1106. The software, when executed by theprocessor 1204, causes the processing system 1114 to perform the variousfunctions described below for any particular apparatus. Thecomputer-readable medium 1106 may also be used for storing data that ismanipulated by the processor 1104 when executing software.

In some aspects of the disclosure, the processor 1104 may includeconnectivity request processing circuitry 1141 configured to receive andprocess connectivity requests from UEs. The connectivity requests may bereceived from the UE or an interworking gateway between the UE and thenext generation core network, and may be included in NAS messages. Theconnectivity requests may include an attach request and may contain aset of capabilities of the UE. The set of capabilities may include, forexample, an indication of whether the UE supports legacy and/or nextgeneration RATs and an indication of whether the UE supports aninter-RAT handover (i.e., between legacy and next generation ANs)initiated by the UE. The connectivity request processing circuitry 1141may process the request based on the UE capabilities, the UE profile,network policies and other factors.

In some examples, the core network serving node 1100 may be a CP-SM,CP-MM and/or eMME that receives a connectivity request from a UE withina next generation wireless access network (AN). The connectivity requestprocessing circuitry 1141 may use the set of capabilities, a UE profile,network policies, and other factors, to select a Quality of Service(QoS) associated with the connectivity to the UE. The QoS parameters mayinclude both legacy and next generation QoS parameters. The connectivityrequest processing circuitry 1141 may then establish a data networksession (DNS) connection between the UE and an external data networkover the next generation AN via the next generation core network.

In some examples, the core network serving node 1100 may be an MME thatreceives a connectivity request from a UE within a legacy wirelessaccess network (AN). Based on the set of capabilities, the connectivityrequest processing circuitry 1141 may determine that the UE supports thenext generation RAT, select an eMME (interworking core network servingnode) serving the current tracking area of the UE associated with thelegacy AN, and redirect the connectivity request to the selected eMME.For example, the connectivity request processing circuitry 1141 mayaccess a configuration table (e.g., within memory 1105) maintaining alist of eMMEs and select the eMME from the list.

In some examples, the core network serving node 1100 may be aninterworking core network serving node (i.e., eMME) that receives aconnectivity request from a UE within a legacy AN. The connectivityrequest may be redirected to the eMME from an MME within a legacy corenetwork. The connectivity request processing circuitry 1141 may processthe connectivity request and select one or more Quality of Service (QoS)parameters, which may include both legacy and next generation QoSparameters, to be associated with the connectivity to the UE. Theconnectivity request processing circuitry 1141 may further authenticatethe UE and/or trigger an MM context establishment towards a nextgeneration core network serving node (e.g., CP-MM) to performauthentication of the UE. The connectivity request processing circuitry1141 may further establish a packet data network (PDN) connection overthe legacy AN between the UE and a UP-GW via the next generation corenetwork. During the PDN connection establishment, the eMME may act as aCP-SM or the connectivity request processing circuitry may involve aCP-SM to anchor the SM context. The connectivity request processingcircuitry 1141 may operate in coordination with connectivity requestprocessing software 1151.

The processor 1104 may further include handover management processingcircuitry 1142 configured to determine whether the UE supports aUE-initiated inter-RAT handover based on the set of capabilities and todetermine whether the next generation core network supports aUE-initiated inter-RAT handover. The handover management processingcircuitry may further provide an indication to the UE or theinterworking gateway of whether the next generation core network supporta UE-initiated inter-RAT handover upon successfully establishingconnectivity to the UE.

In some examples, the core network serving node 1100 is a CP-MM or CP-SMthat receives a handover request from a next generation AN indicatingthat a handover should be performed from the next generation AN to alegacy AN for a UE currently served by the next generation AN. Thehandover request may include, for example, the cell ID of the targetcell in the legacy AN, a descriptor of next generation AN resources(e.g., configuration of radio bearer, security information, etc.), andother information. The handover management processing circuitry 1142 maythen determine the identity of an eMME to process the handover request.For example, the identity of the eMME may be included in the handoverrequest or the handover management processing circuitry 1142 maydetermine the identity of the eMME based on the target cell ID of thelegacy AN. The handover management processing circuitry 1142 may thenforward the handover request to the eMME for further processing.

In some examples, the core network serving node 1100 is an eMME thatreceives the handover request from the CP-MM or CP-SM. In this example,the handover management processing circuitry 1142 may identify an MMEand target eNB within the legacy core network based on the target cellID and forward the handover request to the MME and target eNB. Inaddition, the handover management processing circuitry 1142 may furtherconvert next generation AN resources information into legacy accessinformation and provide the legacy access information to the MME. Thehandover management processing circuitry 1142 may further provide to theMME legacy specific QoS parameters established when the QoS wasestablished in the next generation AN.

In addition, the handover management processing circuitry 1142 in theeMME may further map next generation IP flows to PDN connections. Invarious aspects of the present disclosure, the handover managementprocessing circuitry 1142 may map each IP flow to a PDN connection basedon at least the external data network associated with the IP flow. Insome examples, the characteristics of the IP flows (e.g., QoS, packetprocessing requirements, etc.) may further be used to map IP flows toPDN connections. In some examples, multiple IP addresses (multiple IPflows) may be supported on a single PDN connection.

The handover management processing circuitry 1142 may provide mappinginformation indicating the mapping of IP flows to PDN connections (e.g.,GTP tunnels) to the eSGW in the next generation core network to enablethe eSGW to map IP flows received on the downlink from UP-GWs to thecorresponding PDN connections (e.g., GTP tunnels) to the legacy AN. Onthe uplink, PDU's received by the eSGW may also be mapped to theappropriate IP flows or GTP tunnels and routed to the appropriate UP-GWsbased on the mapping information. Thus, in examples in which the corenetwork serving node 1100 is an eSGW, the handover management processingcircuitry 1142 may utilize the mapping information to map IP flows toPDN connections and GTP tunnels within the PDN connections.

In some examples, the core network serving node 1100 is an eMME thatreceives a handover request from a legacy AN (e.g., legacy eNB) orlegacy MME. In this example, the handover request may be requesting ahandover of a UE from a legacy AN to a next generation AN. The handovermanagement processing circuitry 1142 may use the target cell ID (of thenext generation target cell) to select a CP-MM and/or CP-SM and forwardthe handover request to the CP-MM and/or CP-SM. The handover managementprocessing circuitry 1142 may further convert handover information(e.g., configuration of radio bearers, etc.) provided by the legacyAN/legacy MME into next generation configuration information and includethe next generation configuration information in the handover requestsent the CP-MM and/or CP-SM.

In some examples, the core network serving node 1100 is a CP-MM and/orCP-SM that receives the handover request from the eMME. In this example,the handover request may be requesting a handover of a UE from a legacyAN to a next generation AN. The handover management processing circuitry1142 may select a next generation AN corresponding to the target cell IDand interact with the next generation AN to establish the connectivityand context for the handover. The handover management processingcircuitry 1142 may operate in coordination with handover managementprocessing software 1152.

The processor 1104 may further include QoS selection circuitry 1143configured to select one or more QoS parameters to associate to theconnectivity to the UE. The QoS selection circuitry 1143 may select oneor more QoS parameters and establish values for the one or more selectedQoS parameters based on the UE capabilities and network policies. Insome examples, if the set of capabilities indicates that the UE supportsthe legacy RAT and includes one or more QoS parameters used in legacynetworks (e.g., Guaranteed Bit Rate (GBR) and/or specific QoS ClassIdentifiers (CQIs)), the QoS selection circuitry 1143 may select one ormore QoS parameters associated with the next generation core network andone or more QoS parameters associated with the legacy AN to enableinterworking with the legacy network in case of a handover from the nextgeneration AN to the legacy AN. The QoS selection circuitry 1143 maystore the QoS parameters within, for example, memory 1105 or may forwardthe QoS parameters to another core network serving node (e.g., CP-MMand/or CP-SM) upon connectivity establishment. The QoS selectioncircuitry 1143 may further provide the QoS parameters to the eMME uponhandover to a legacy AN. The QoS selection circuitry 1143 may operate incoordination with QoS selection software 1153.

One or more processors 1104 in the processing system may executesoftware. Software shall be construed broadly to mean instructions,instruction sets, code, code segments, program code, programs,subprograms, software modules, applications, software applications,software packages, routines, subroutines, objects, executables, threadsof execution, procedures, functions, etc., whether referred to assoftware, firmware, middleware, microcode, hardware descriptionlanguage, or otherwise. The software may reside on a computer-readablemedium 1106. The computer-readable medium 1106 may be a non-transitorycomputer-readable medium. A non-transitory computer-readable mediumincludes, by way of example, a magnetic storage device (e.g., hard disk,floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD)or a digital versatile disc (DVD)), a smart card, a flash memory device(e.g., a card, a stick, or a key drive), a random access memory (RAM), aread only memory (ROM), a programmable ROM (PROM), an erasable PROM(EPROM), an electrically erasable PROM (EEPROM), a register, a removabledisk, and any other suitable medium for storing software and/orinstructions that may be accessed and read by a computer. Thecomputer-readable medium may also include, by way of example, a carrierwave, a transmission line, and any other suitable medium fortransmitting software and/or instructions that may be accessed and readby a computer. The computer-readable medium 1106 may reside in theprocessing system 1114, external to the processing system 1114, ordistributed across multiple entities including the processing system1114. The computer-readable medium 1106 may be embodied in a computerprogram product. By way of example, a computer program product mayinclude a computer-readable medium in packaging materials. Those skilledin the art will recognize how best to implement the describedfunctionality presented throughout this disclosure depending on theparticular application and the overall design constraints imposed on theoverall system.

FIG. 12 is a conceptual diagram illustrating an example of a hardwareimplementation for an exemplary UE 202 employing a processing system1214. In accordance with various aspects of the disclosure, an element,or any portion of an element, or any combination of elements may beimplemented with a processing system 1214 that includes one or moreprocessors 1204.

The processing system 1214 may be substantially the same as theprocessing system 1114 illustrated in FIG. 11, including a bus interface1208, a bus 1202, memory 1205, a processor 1204, and a computer-readablemedium 1206. Furthermore, the UE 202 may include a user interface 1212and a transceiver 1210 for communicating with various other apparatusover a transmission medium (e.g., air interface). The processor 1204, asutilized in a UE 202, may be used to implement any one or more of theprocesses described below.

In some aspects of the disclosure, the processor 1204 may include uplink(UL) data and control channel generation and transmission circuitry1242, configured to generate and transmit uplink data on an UL datachannel, and to generate and transmit uplinkcontrol/feedback/acknowledgement information on an UL control channel.The UL data and control channel generation and transmission circuitry1242 may operate in coordination with UL data and control channelgeneration and transmission software 1252. The processor 1204 mayfurther include downlink (DL) data and control channel reception andprocessing circuitry 1244, configured for receiving and processingdownlink data on a data channel, and to receive and process controlinformation on one or more downlink control channels. In some examples,received downlink data and/or control information may be stored withinmemory 1205. The DL data and control channel reception and processingcircuitry 1244 may operate in coordination with DL data and controlchannel reception and processing software 1254.

The processor 1204 may further include interworking processing circuitry1246, configured for interworking between a legacy AN and a nextgeneration core network. The interworking processing circuitry 1246 maytransmit a connectivity request (including an attach request) to thenext generation core network through a wireless access network (legacyor next generation). If through a legacy AN, the connectivity requestmay be sent within NAS messages. The connectivity request may include aset of capabilities of the UE, including an indication of whether the UEsupports legacy and/or next generation RATs and an indication of whetherthe UE supports an inter-RAT handover (i.e., between legacy and nextgeneration ANs) initiated by the UE. The interworking processingcircuitry 1246 may further receive an indication of whether the nextgeneration core network supports UE-initiated inter-RAT handovers.

In some examples, the interworking processing circuitry 1246 may furtherreceive IP flow-PDN connection mapping information upon a handover froma next generation AN to a legacy AN. The interworking processingcircuitry 1246 may further encapsulate IP flow PDU's into PDN PDU's forrouting over the appropriate tunnels. The interworking processingcircuitry 1246 may further operate in coordination with interworkingprocessing software 1256.

One or more processors 1204 in the processing system may executesoftware. Software shall be construed broadly to mean instructions,instruction sets, code, code segments, program code, programs,subprograms, software modules, applications, software applications,software packages, routines, subroutines, objects, executables, threadsof execution, procedures, functions, etc., whether referred to assoftware, firmware, middleware, microcode, hardware descriptionlanguage, or otherwise. The software may reside on a computer-readablemedium 1206. The computer-readable medium 1206 may be a non-transitorycomputer-readable medium. A non-transitory computer-readable mediumincludes, by way of example, a magnetic storage device (e.g., hard disk,floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD)or a digital versatile disc (DVD)), a smart card, a flash memory device(e.g., a card, a stick, or a key drive), a random access memory (RAM), aread only memory (ROM), a programmable ROM (PROM), an erasable PROM(EPROM), an electrically erasable PROM (EEPROM), a register, a removabledisk, and any other suitable medium for storing software and/orinstructions that may be accessed and read by a computer. Thecomputer-readable medium may also include, by way of example, a carrierwave, a transmission line, and any other suitable medium fortransmitting software and/or instructions that may be accessed and readby a computer. The computer-readable medium 1206 may reside in theprocessing system 1214, external to the processing system 1214, ordistributed across multiple entities including the processing system1214. The computer-readable medium 1206 may be embodied in a computerprogram product. By way of example, a computer program product mayinclude a computer-readable medium in packaging materials. Those skilledin the art will recognize how best to implement the describedfunctionality presented throughout this disclosure depending on theparticular application and the overall design constraints imposed on theoverall system.

FIG. 13 is a flow chart 1300 of a method for interworking between corenetworks in a communication network. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by a legacy core networkserving node, such as a MME, as described above and illustrated in FIG.11, by a processor or processing system, or by any suitable means forcarrying out the described functions.

At block 1302, the legacy core network serving node (e.g., MME) mayreceive a connectivity request from a UE via a legacy wireless accessnetwork (AN) utilizing a legacy RAT. For example, the MME in the legacycore network may receive a non-access stratum (NAS) message including aset of capabilities of the UE. The set of capabilities may include, forexample, an indication of whether the UE supports legacy and/or nextgeneration RATs and an indication of whether the UE supports aninter-RAT handover (i.e., between legacy and next generation ANs)initiated by the UE.

At block 1304, the MME may determine that the UE supports a second RAT.For example, the MME may determine that the UE supports a nextgeneration RAT based on the set of capabilities of the UE and/or a userprofile/subscription. At block 1306, the MME may select an interworkingcore network serving node (e.g., eMME) for interworking between thelegacy core network and a next generation core network supporting thenext generation RAT, and at block 1308, transfer the connectivityrequest to the eMME to establish and relocate connectivity of the UE tothe next generation core network. For example, the MME may access aconfiguration table maintaining a list of eMMEs and select the eMME thatserves a current tracking area of the UE associated with the legacywireless AN. The MME may then forward the connectivity request to theselected eMME or redirect the connectivity request to the selected eMMEvia the legacy AN and an interworking serving gateway (eSGW).

FIG. 14 is a flow chart 1400 of a method for interworking between corenetworks in a communication network. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by a legacy core networkserving node, such as a MME, as described above and illustrated in FIG.11, by a processor or processing system, or by any suitable means forcarrying out the described functions.

At block 1402, the legacy core network serving node receives aconnectivity request from a UE via a legacy wireless access network (AN)utilizing a legacy RAT. For example, the MME in the legacy core networkmay receive a non-access stratum (NAS) message including a set ofcapabilities of the UE. The set of capabilities may include, forexample, an indication of whether the UE supports legacy and/or nextgeneration RATs and an indication of whether the UE supports aninter-RAT handover (i.e., between legacy and next generation ANs)initiated by the UE.

At block 1404, the legacy core network serving node (e.g., MME) maydetermine whether the UE supports a second RAT. For example, the MME maydetermine whether the UE supports a next generation RAT based on the setof capabilities of the UE and/or a user profile/subscription. If the UEdoes not support a next generation RAT (N branch of block 1404), atblock 1406, the MME processes the connectivity request over the legacycore network. For example, the MME may authenticate the UE, establish aPacket Data Network (PDN) connection between the UE and a PDN Gatewayvia the legacy AN, and select one or more QoS parameters for the PDNconnection.

If the UE does support a next generation RAT (Y branch of block 1404),at block 1408, the MME may access a configuration table with a list ofinterworking core network serving nodes (e.g., eMMEs). At block 1410,the MME may select the eMME serving the current tracking area of the UEfrom the configuration table, and at block 1412, transfer theconnectivity request to the selected eMME. For example, the MME mayforward the connectivity request to the selected eMME or redirect theconnectivity request to the selected eMME via the legacy AN and aninterworking serving gateway (eSGW).

FIG. 15 is a flow chart 1500 of a method for interworking between corenetworks in a communication network. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by an interworking corenetwork serving node, such as an eMME, as described above andillustrated in FIG. 11, by a processor or processing system, or by anysuitable means for carrying out the described functions.

At block 1502, the interworking core network serving node (e.g., eMME)within a next generation core network may receive a redirectedconnectivity request from a UE in wireless communication with a basestation within a legacy wireless access network that utilizes a legacyRAT. The connectivity request may have been originated by the UE towardsa legacy core network and redirected to the eMME via, for example, aninterworking serving gateway (eSGW). The connectivity request mayinclude, for example, a set of capabilities of the UE. The set ofcapabilities may include, for example, an indication of whether the UEsupports legacy and/or next generation RATs and an indication of whetherthe UE supports an inter-RAT handover (i.e., between legacy and nextgeneration ANs) initiated by the UE.

At block 1504, the eMME may process the connectivity request based on atleast an indication that the UE supports the next generation RAT. Forexample, the eMME may authenticate the UE or may select another nextgeneration core network serving node (e.g., CP-MM/CP-SM) within the nextgeneration network to authenticate the UE. At block 1506, the eMME mayestablish connectivity to the UE upon successfully processing theconnectivity request. The eMME may then provide an indication to the UEof whether the next generation core network supports UE-initiatedinter-RAT handovers In addition, the eMME may further select a qualityof service (QoS) to associate with the connectivity to the UE. The QoSmay include, for example, both legacy and next generation QoSparameters.

FIG. 16 is a flow chart 1600 of a method for interworking between corenetworks in a communication network. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by an interworking corenetwork serving node, such as an eMME, as described above andillustrated in FIG. 11, by a processor or processing system, or by anysuitable means for carrying out the described functions.

At block 1602, the interworking core network serving node (e.g., eMME)may receive a redirected connectivity request from a UE in wirelesscommunication with a base station within a legacy wireless accessnetwork that utilizes a legacy RAT. The connectivity request may havebeen originated by the UE towards a legacy core network and redirectedto the eMME via, for example, an interworking serving gateway (eSGW).The connectivity request may include, for example, a set of capabilitiesof the UE. The set of capabilities may include, for example, anindication of whether the UE supports legacy and/or next generation RATsand an indication of whether the UE supports an inter-RAT handover(i.e., between legacy and next generation ANs) initiated by the UE.

At block 1604, the eMME may select one or more Quality of Service (QoS)parameters to associate with the connectivity to the UE based on the setof capabilities. The QoS parameters may include, for example, bothlegacy and next generation QoS parameters. At block 1606, the eMME mayauthenticate the UE based on at least the set of capabilities. In someexamples, the UE may establish an enhanced mobile management (EMM)context with the eMME and authenticates with the eMME using legacymechanisms. For example, the eMME may interact with an Authentication,Authorization and Accounting (AAA) server/HSS to retrieve the subscriberprofile for the UE and perform authentication and key derivation tosecure the radio link

At block 1608, the eMME may select a User Plane Gateway (UP-GW) for theconnection, and at block 1610, establish a Packet Data Network (PDN)connection between the UE and the UP-GW over the next generation corenetwork and the legacy AN. For example, the eMME may select the UP-GWhaving a connection to a destination external data network for the PDNconnection and establish the PDN connection between the UE and UP-GW viaan interworking gateway (e.g., an evolved serving gateway).

FIG. 17 is a flow chart 1700 of a method for interworking between corenetworks to authenticate a UE in a communication network. As describedbelow, some or all illustrated features may be omitted in a particularimplementation within the scope of the present disclosure, and someillustrated features may not be required for implementation of allembodiments. In some examples, the method may be performed by aninterworking core network serving node, such as an eMME, as describedabove and illustrated in FIG. 11, by a processor or processing system,or by any suitable means for carrying out the described functions.

At block 1702, the interworking core network serving node (e.g., eMME)may receive a redirected connectivity request from a UE in wirelesscommunication with a base station within a legacy wireless accessnetwork that utilizes a legacy RAT. The connectivity request may havebeen originated by the UE towards a legacy core network and redirectedto the eMME via, for example, an interworking serving gateway (eSGW).The connectivity request may include, for example, a set of capabilitiesof the UE. The set of capabilities may include, for example, anindication of whether the UE supports legacy and/or next generation RATsand an indication of whether the UE supports an inter-RAT handover(i.e., between legacy and next generation ANs) initiated by the UE.

At block 1704, the eMME may determine whether the mobility management(MM) context is anchored in the eMME. If the MM context is anchored inthe eMME (Y branch of 1704), at block 1706, the eMME may authenticatethe UE using legacy mechanisms. For example, the eMME may interact withan Authentication, Authorization and Accounting (AAA) server/HSS (notshown) to retrieve the subscriber profile for the UE and performauthentication and key derivation to secure the radio link.

If the MM context is not anchored in the eMME (N branch of 1704), at1708, the eMME may trigger MM context establishment towards the CP-MM.For example, the eMME may select a serving CP-MM based on preconfiguredinformation (e.g., based on the location of the serving legacy cell),and trigger an MM context establishment towards the selected CP-MM. Atblock 1710, the eMME may authenticate the UE via the CP-MM. For example,the CP-MM may interact with the AAA/HSS to retrieve the subscriberprofile and perform the authentication and key derivation to secure theradio link.

FIG. 18 is a flow chart 1800 of a method for interworking between corenetworks to provide multiple data connection (e.g., IP) addresses in acommunication network. As described below, some or all illustratedfeatures may be omitted in a particular implementation within the scopeof the present disclosure, and some illustrated features may not berequired for implementation of all embodiments. In some examples, themethod may be performed by an interworking core network serving node,such as an eMME, as described above and illustrated in FIG. 11, by aprocessor or processing system, or by any suitable means for carryingout the described functions.

At block 1802, the interworking core network serving node (e.g., eMME)may establish a Packet Data Network (PDN) connection between a UE and aselected UP-GW over the next generation core network and a legacy ANserving the UE. For example, the eMME may select the UP-GW having aconnection to a destination external data network for the PDN connectionand establish the PDN connection between the UE and UP-GW via aninterworking gateway (e.g., an evolved serving gateway). At block 1804,the eMME may provide an IP address to the UE assigned to the UE by theUP-GW for the PDN connection.

At block 1806, the eMME may determine whether the PDN connectionsupports multiple IP addresses. If the PDN connection does not supportmultiple IP addresses (N branch of block 1806), at block 1808, the eMMEmay provide an indication to the UE that the PDN connection does notsupport multiple IP addresses. If the PDN connection does supportmultiple IP addresses (Y branch of block 1808), at block 1810, the eMMEmay provide an indication to the UE that the PDN connection supportsmultiple IP addresses. At block 1812, the eMME may then provide a set ofinformation to be used by the UE to request additional IP addresses. Theset of information may include, for example, an address corresponding tothe serving UP-GW that enables the UE to request additional IP addressesfrom the UP-GW.

FIG. 19 is a flow chart 1900 of a method for interworking between corenetworks to provide multiple data connection (e.g., IP) addresses in acommunication network. As described below, some or all illustratedfeatures may be omitted in a particular implementation within the scopeof the present disclosure, and some illustrated features may not berequired for implementation of all embodiments. In some examples, themethod may be performed by an interworking core network serving node,such as an eMME, as described above and illustrated in FIG. 11, by aprocessor or processing system, or by any suitable means for carryingout the described functions.

At block 1902, the interworking core network serving node (e.g., eMME)may establish a first Packet Data Network (PDN) connection between a UEand a selected UP-GW over the next generation core network and a legacyAN serving the UE. For example, the eMME may select the UP-GW having aconnection to a destination external data network for the first PDNconnection and establish the first PDN connection between the UE andUP-GW via an interworking gateway (e.g., an evolved serving gateway). Atblock 1904, the eMME may provide an IP address to the UE assigned to theUE by the UP-GW for the first PDN connection.

At block 1906, the eMME may determine whether the next generation corenetwork supports multiple IP addresses for the UE through the legacy AN.If the next generation core network does not support multiple IPaddresses (N branch of block 1906), at block 1908, the eMME may providean indication to the UE that the next generation core network does notsupport multiple IP addresses for the UE through the legacy AN. If thenext generation core network does support multiple IP addresses (Ybranch of block 1908), at block 1910, the eMME may provide an indicationto the UE that the next generation core network supports multiple IPaddresses for the UE.

At block 1912, the eMME may then receive a request from the UE for a newIP address for a new PDN connection. For example, the eMME may receivean enhanced NAS signal from the UE requesting a new IP addresses andproviding the connectivity requirements for the new IP address/PDNconnection (e.g., the type of session continuity required). At block1914, the eMME may then verify that the UE is authorized to request anew IP address and process the information provided by the UE. At block1916, the eMME may then select a new UP-GW for the new PDN connection,which assigns the new IP address, and at block 1918, establish the newPDN connection between the UE and the new UP-GW over the next generationcore network and the legacy AN. At block 1920, the eMME may then returnthe new IP address to the UE.

FIG. 20 is a flow chart 2000 of a method for establishing connectivityto a next generation communication network. As described below, some orall illustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by a next generation corenetwork serving node, such as a CP-MM and/or CP-SM, as described aboveand illustrated in FIG. 11, by a processor or processing system, or byany suitable means for carrying out the described functions.

At block 2002, the next generation core network serving node within anext generation core network may receive a connectivity request from aUE in wireless communication with a base station within a nextgeneration wireless access network that utilizes a next generation RAT.The connectivity request may include, for example, a set of capabilitiesof the UE. The set of capabilities may include, for example, anindication of whether the UE supports legacy and/or next generation RATsand an indication of whether the UE supports an inter-RAT handover(i.e., between legacy and next generation ANs) initiated by the UE.

At block 2004, the next generation core network serving node may processthe connectivity request at the next generation core network. Forexample, the next generation core network serving node may establish adata network session (DNS) connection between the UE and an externaldata network over the next generation AN via the next generation corenetwork. At block 2006, the next generation core network serving nodemay then provide an indication to the UE of whether the next generationcore network supports an inter-RAT handover. For example, the nextgeneration core network serving node may indicate whether the nextgeneration core network supports inter-RAT handovers initiated by the UEor whether the UE is allowed to perform inter-RAT handovers.

FIG. 21 is a flow chart 2100 of a method for establishing connectivityto a next generation communication network. As described below, some orall illustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by a next generation corenetwork serving node, such as a CP-MM and/or CP-SM, as described aboveand illustrated in FIG. 11, by a processor or processing system, or byany suitable means for carrying out the described functions.

At block 2102, the next generation core network serving node within anext generation core network may receive a connectivity request from aUE in wireless communication with a base station within a nextgeneration wireless access network that utilizes a next generation RAT.The connectivity request may include, for example, a set of capabilitiesof the UE. The set of capabilities may include, for example, anindication of whether the UE supports legacy and/or next generation RATsand an indication of whether the UE supports an inter-RAT handover(i.e., between legacy and next generation ANs) initiated by the UE.

At block 2104, the next generation core network serving node maydetermine whether the UE supports connectivity to a legacy RAT based onthe set of capabilities. If the UE does support connectivity to a legacyRAT (Y branch of 2104), at block 2106, the next generation core networkserving node may establish values for one or more legacy QoS parameters.In some examples, the set of capabilities may include at least a portionof the legacy QoS parameters for the UE. In other examples, the corenetwork serving node may retrieve or derive one or more of the legacyQoS parameters from a UE profile, network policies and/or other factors.

If the UE does not support connectivity to a legacy RAT (N branch of2104) or after establishing legacy QoS parameters at block 2106, atblock 2108, the next generation core network serving node may establishvalues for one or more next generation QoS parameters. For example, thenext generation core network serving node may use one or more of the setof capabilities, UE profile, network policies and other factors toselect the next generation QoS parameters and establish values for thenext generation QoS parameters.

FIG. 22 is a flow chart 2200 of a method for performing a handoverbetween core networks in a communication network. As described below,some or all illustrated features may be omitted in a particularimplementation within the scope of the present disclosure, and someillustrated features may not be required for implementation of allembodiments. In some examples, the method may be performed by a nextgeneration core network serving node, such as an eMME, CP-MM and/orCP-SM, as described above and illustrated in FIG. 11, by a processor orprocessing system, or by any suitable means for carrying out thedescribed functions.

At block 2202, the next generation core network serving node may receivea handover request for handing over a UE from a next generation wirelessaccess network (next generation AN) utilizing a next generation RAT to alegacy wireless access network (legacy AN) utilizing a legacy RAT. Thehandover request may include an identifier of a target cell within thelegacy AN. In some examples, a CP-MM and/or CP-SM may receive thehandover request from the next generation AN. The handover request mayinclude an identity of an eMME for handling the handover request or theCP-MM and/or CP-SM may determine the identity of the eMME based on thetarget cell ID. The CP-MM and/or CP-SM may then forward the handoverrequest to the eMME. In other examples, the eMME receives the handoverrequest (e.g., from the CP-MM and/or CP-SM or the next generation AN).

At block 2204, the next generation core network serving node (e.g.,eMME) may identify a legacy core network serving node (e.g., MME) basedon the target cell ID. At block 2206, the next generation core networkserving node (e.g., eMME) may then forward the handover request to thelegacy core network serving node (e.g., MME) to complete the handover.

FIG. 23 is a flow chart 2300 of a method for performing a handoverbetween core networks in a communication network. As described below,some or all illustrated features may be omitted in a particularimplementation within the scope of the present disclosure, and someillustrated features may not be required for implementation of allembodiments. In some examples, the method may be performed by aninterworking core network serving node, such as an eMME, as describedabove and illustrated in FIG. 11, by a processor or processing system,or by any suitable means for carrying out the described functions.

At block 2302, the eMME may receive a handover request for handing overa UE from a next generation wireless access network (next generation AN)utilizing a next generation RAT to a legacy wireless access network(legacy AN) utilizing a legacy RAT. The handover request may include anidentifier of a target cell within the legacy AN. In some examples, aCP-MM and/or CP-SM may receive the handover request from the nextgeneration AN. The handover request may include an identity of an eMMEfor handling the handover request or the CP-MM and/or CP-SM maydetermine the identity of the eMME based on the target cell ID. TheCP-MM and/or CP-SM may then forward the handover request to the eMME.

At block 2304, the eMME may identify a legacy core network serving node(e.g., MME) based on the target cell ID. At block 2306, the eMME mayconvert next generation resource information (e.g., radio bearerconfiguration, security information, etc.) into legacy accessinformation. At block 2308, the eMME may then forward the handoverrequest and legacy access information to the MME. At block 2310, theeMME may further determine whether legacy QoS information is available.For example, legacy QoS information may be established when the QoS wasoriginally established in the next generation AN. If legacy QoSinformation is available (Y branch of block 2310), at block 2312, theeMME may further forward the legacy QoS information to the MME.

FIG. 24 is a flow chart 2400 of a method for performing a handoverbetween core networks in a communication network. As described below,some or all illustrated features may be omitted in a particularimplementation within the scope of the present disclosure, and someillustrated features may not be required for implementation of allembodiments. In some examples, the method may be performed by aninterworking core network serving node, such as an eMME, as describedabove and illustrated in FIG. 11, by a processor or processing system,or by any suitable means for carrying out the described functions.

At block 2402, the eMME may receive a handover request for handing overa UE from a next generation wireless access network (next generation AN)utilizing a next generation RAT to a legacy wireless access network(legacy AN) utilizing a legacy RAT. In some examples, a CP-MM and/orCP-SM may receive the handover request from the next generation AN. Thehandover request may include an identity of an eMME for handling thehandover request or the CP-MM and/or CP-SM may determine the identity ofthe eMME based on the target cell ID. The CP-MM and/or CP-SM may thenforward the handover request to the eMME.

At block 2404, the eMME may identify IP flows to be handed over from thenext generation AN to the legacy AN network. At block 2406, the eMME maymap an IP flow to a Packet Data Network (PDN) connection and a GenericTunneling Protocol (GTP) tunnel within the PDN connection forcommunicating over the legacy AN. For example, the eMME may map each IPflow to a PDN connection based on at least the external data networkassociated with the IP flow. In some examples, the characteristics ofthe IP flows (e.g., QoS, packet processing requirements, etc.) mayfurther be used to map IP flows to PDN connections.

At block 2408, the eMME determines whether there are additional IP flowsinvolved in the handover. If there are additional IP flows (Y branch of2408), at block 2406, the eMME maps another IP flow to PDN connectionand a GTP tunnel within the PDN connection for communicating over thelegacy AN. If there are no additional IP flows (N branch of 2408), atblock 2410, the eMME provides mapping information indicating the mappingof IP flows to PDN connections and GTP tunnels to an interworkingserving gateway within the next generation core network. At block 2412,the eMME further provides the mapping information to the UE for use bythe UE in encapsulating IP flow PDUs into PDN PDUs.

FIG. 25 is a flow chart 2500 of a method for routing IP flows afterperforming a handover between core networks in a communication network.As described below, some or all illustrated features may be omitted in aparticular implementation within the scope of the present disclosure,and some illustrated features may not be required for implementation ofall embodiments. In some examples, the method may be performed by aninterworking core network serving node, such as an eSGW, as describedabove and illustrated in FIG. 11, by a processor or processing system,or by any suitable means for carrying out the described functions.

At block 2502, the eSGW may receive mapping information indicating themapping of next generation IP flows to legacy PDN connections and GTPtunnels after a handover from a next generation RAT to a legacy RAT hasbeen performed. At block 2504, the eSGW may further receive a PDU forrouting. At block 2506, the eSGW determines whether the PDU is an uplinkPDU or a downlink PDU. If the PDU is an uplink PDU (Y branch of block2506), at blocks 2508 and 2510, the eSGW decapsulates the IP flow PDUfrom the PDN PDU and maps the IP flow PDU to the correct IP flow basedon the mapping information. For example, the eSGW may identify thecorrect IP flow based on the IP addresses (UE and UP-GW) in the IP flowPDU. At block 2512, the eSGW may route the IP flow PDU to the UP-GWassociated with the IP flow.

If the PDU is not a downlink PDU (N branch of block 2506), at block2514, the eSGW maps the IP flow to the PDN connection and GTP tunnelbased on the mapping information. For example, the eSGW may identify thePDN connection and GTP tunnel based on the IP addresses (UE and UP-GW)in the IP flow PDU. At block 2516, the eSGW may encapsulate the IP flowPDU into a PDN PDU for the PDN connection and GTP tunnel. At 2518, theeSGW may route the PDN PDU over the GTP tunnel within the PDN connectionto the UE.

FIG. 26 is a flow chart 2600 of a method for performing a handoverbetween core networks in a communication network. As described below,some or all illustrated features may be omitted in a particularimplementation within the scope of the present disclosure, and someillustrated features may not be required for implementation of allembodiments. In some examples, the method may be performed by aninterworking core network serving node, such as an eMME, as describedabove and illustrated in FIG. 11, by a processor or processing system,or by any suitable means for carrying out the described functions.

At block 2602, the eMME may receive a handover request for handing overa UE from a legacy wireless access network (legacy AN) utilizing alegacy RAT to a next generation wireless access network (next generationAN) utilizing a next generation RAT. The handover request may include anidentifier of a target cell within the next generation AN. For example,the eMME may receive the handover request from an eNB within the legacyAN or an MME within a legacy core network.

At block 2604, the eMME may identify a next generation core networkserving node (e.g., CP-MM and/or CP-SM) based on the target cell ID. Atblock 2606, the next generation core network serving node (e.g., eMME)may then forward the handover request to the CP-MM and/or CP-SM tocomplete the handover.

FIG. 27 is a flow chart 2700 of a method for performing a handoverbetween core networks in a communication network. As described below,some or all illustrated features may be omitted in a particularimplementation within the scope of the present disclosure, and someillustrated features may not be required for implementation of allembodiments. In some examples, the method may be performed by a nextgeneration core network serving node, such as a CP-MM and/or CP-SM, asdescribed above and illustrated in FIG. 11, by a processor or processingsystem, or by any suitable means for carrying out the describedfunctions.

At block 2702, the next generation core network serving node may receivea handover request for handing over a UE from a legacy wireless accessnetwork (legacy AN) utilizing a legacy RAT to a next generation wirelessaccess network (next generation AN) utilizing a next generation RAT. Thehandover request may include an identifier of a target cell within thenext generation AN. For example, the CP-MM and/or CP-SM may receive thehandover request from an eMME within the next generation core network.

At block 2704, the next generation core network serving node may selecta next generation AN based on the target cell ID. At block 2706, thenext generation core network serving node may then communicate with thenext generation AN to establish connectivity and context for thehandover.

Several aspects of a wireless communication network have been presentedwith reference to an exemplary implementation. As those skilled in theart will readily appreciate, various aspects described throughout thisdisclosure may be extended to other telecommunication systems, networkarchitectures and communication standards.

By way of example, various aspects may be implemented within othersystems defined by 3GPP, such as Long-Term Evolution (LTE), the EvolvedPacket System (EPS), the Universal Mobile Telecommunication System(UMTS), and/or the Global System for Mobile (GSM). Various aspects mayalso be extended to systems defined by the 3rd Generation PartnershipProject 2 (3GPP2), such as CDMA2000 and/or Evolution-Data Optimized(EV-DO). Other examples may be implemented within systems employing IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB),Bluetooth, and/or other suitable systems. The actual telecommunicationstandard, network architecture, and/or communication standard employedwill depend on the specific application and the overall designconstraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean“serving as an example, instance, or illustration.” Any implementationor aspect described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other aspects of thedisclosure. Likewise, the term “aspects” does not require that allaspects of the disclosure include the discussed feature, advantage ormode of operation. The term “coupled” is used herein to refer to thedirect or indirect coupling between two objects. For example, if objectA physically touches object B, and object B touches object C, thenobjects A and C may still be considered coupled to one another—even ifthey do not directly physically touch each other. For instance, a firstobject may be coupled to a second object even though the first object isnever directly physically in contact with the second object. The terms“circuit” and “circuitry” are used broadly, and intended to include bothhardware implementations of electrical devices and conductors that, whenconnected and configured, enable the performance of the functionsdescribed in the present disclosure, without limitation as to the typeof electronic circuits, as well as software implementations ofinformation and instructions that, when executed by a processor, enablethe performance of the functions described in the present disclosure.

One or more of the components, steps, features and/or functionsillustrated in FIGS. 1-27 may be rearranged and/or combined into asingle component, step, feature or function or embodied in severalcomponents, steps, or functions. Additional elements, components, steps,and/or functions may also be added without departing from novel featuresdisclosed herein. The apparatus, devices, and/or components illustratedin FIGS. 1-12 may be configured to perform one or more of the methods,features, or steps described herein. The novel algorithms describedherein may also be efficiently implemented in software and/or embeddedin hardware.

It is to be understood that the specific order or hierarchy of steps inthe methods disclosed is an illustration of exemplary processes. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the methods may be rearranged. The accompanyingmethod claims present elements of the various steps in a sample order,and are not meant to be limited to the specific order or hierarchypresented unless specifically recited therein.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but are to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. A phrase referring to“at least one of” a list of items refers to any combination of thoseitems, including single members. As an example, “at least one of: a, b,or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, band c. All structural and functional equivalents to the elements of thevarious aspects described throughout this disclosure that are known orlater come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. No claim element is tobe construed under the provisions of 35 U.S.C. § 112(f) unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

What is claimed is:
 1. A method for interworking between radio accesstechnologies in a communication network, comprising: receiving mappinginformation for a user equipment at a core network serving node within acore network supporting a first radio access technology (RAT) afterhandover of the user equipment from the first RAT to a second RAT,wherein the mapping information indicates a mapping between one or moredata flows within one or more Data Network Session (DNS) connections forcommunicating over the core network and one or more correspondingGeneric Tunneling Protocol (GTP) tunnels within one or morecorresponding Packet Data Network (PDN) connections for communicatingover a wireless access network utilizing the second RAT; receiving apacket data unit (PDU) at the core network serving node; if the PDUcomprises an uplink PDU: decapsulating the uplink PDU from a GTP tunnelof the one or more GTP tunnels within a PDN connection of the one ormore PDN connections to produce a decapsulated PDU; mapping thedecapsulated PDU to a data flow of the one or more data flows based onthe mapping information to produce a data flow PDU; and routing the dataflow PDU to a user plane gateway serving the data flow within the corenetwork.
 2. The method of claim 1, further comprising: if the PDUcomprises a downlink PDU of a data flow of the one or more data flows:mapping the downlink PDU to a GTP tunnel of the one or more GTP tunnelsand a PDN connection of the one or more PDN connections based on themapping information; encapsulating the downlink PDU into a PDN PDU; androuting the PDN PDU over the GTP tunnel within the PDN connection to theuser equipment via the wireless access network.
 3. The method of claim2, wherein: each of the data flows is associated with a differentInternet Protocol (IP) address of the user equipment utilized in thecore network; and each of the corresponding PDN connections isassociated with an additional different IP address of the user equipmentutilized in the wireless access network.
 4. The method of claim 1,wherein a first PDN connection comprises two or more of the data flows,each mapped to a different corresponding GTP tunnel within the first PDNconnection.
 5. The method of claim 1, further comprising: receivingadditional mapping information indicating an additional mapping betweena set of two or more data flows mapped to a first PDN connection to twoor more additional GTP tunnels within the core network, wherein each ofthe two or more additional GTP tunnels provides connectivity to adifferent user plane gateway in the core network.
 6. The method of claim5, wherein routing the data flow PDU to the user plane gateway furthercomprises: routing the data flow PDU over an additional GTP tunnel ofthe one or more additional GTP tunnels based on the additional mappinginformation.
 7. An interworking core network serving node forinterworking between a first core network supporting a first radioaccess technology (RAT) and a second core network supporting a secondRAT, the interworking core network serving node comprising: an interfacecoupled to a wireless access network that utilizes the second RAT; amemory; and a processor communicatively coupled to the interface and thememory, the processor configured to: receive mapping information for auser equipment after handover of the user equipment from the first RATto the second RAT, the mapping information indicating a mapping betweenone or more data flows within one or more Data Network Session (DNS)connections for communicating over the first core network and one ormore corresponding Generic Tunneling Protocol (GTP) tunnels within oneor more corresponding Packet Data Network (PDN) connections forcommunicating over the wireless access network; receive a packet dataunit (PDU); if the PDU comprises an uplink PDU: decapsulate the uplinkPDU from a GTP tunnel of the one or more GTP tunnels within a PDNconnection of the one or more PDN connections to produce a decapsulatedPDU; map the decapsulated PDU to a data flow of the one or more dataflows based on the mapping information to produce a data flow PDU; androute the data flow PDU to a user plane gateway serving the data flowwithin the first core network.
 8. The interworking core network servingnode of claim 7, wherein the processor is further configured to: if thePDU comprises a downlink PDU of a data flow of the one or more dataflows: map the downlink PDU to a GTP tunnel of the one or more GTPtunnels and a PDN connection of the one or more PDN connections based onthe mapping information; encapsulate the downlink PDU into a PDN PDU;and route the PDN PDU over the GTP tunnel within the PDN connection tothe user equipment via the wireless access network.
 9. The interworkingcore network serving node of claim 8, wherein: each of the data flows isassociated with a different Internet Protocol (IP) address of the userequipment utilized in the first core network; and each of thecorresponding PDN connections is associated with an additional differentIP address of the user equipment utilized in the wireless accessnetwork.
 10. The interworking core network serving node of claim 7,wherein a first PDN connection comprises two or more of the data flows,each mapped to a different corresponding GTP tunnel within the first PDNconnection.
 11. The interworking serving node of claim 7, wherein theprocessor is further configured to: receive additional mappinginformation indicating an additional mapping between a set of two ormore data flows mapped to a first PDN connection to two or moreadditional GTP tunnels within the core network, wherein each of the twoor more additional GTP tunnels provides connectivity to a different userplane gateway in the core network.
 12. The interworking serving node ofclaim 11, wherein the processor is further configured to: route the dataflow PDU over an additional GTP tunnel of the one or more additional GTPtunnels based on the additional mapping information.
 13. An interworkingcore network serving node apparatus for interworking between a firstcore network supporting a first radio access technology (RAT) and asecond core network supporting a second RAT, the interworking corenetwork serving node apparatus comprising: means for receiving mappinginformation for a user equipment after handover of the user equipmentfrom the first RAT to the second RAT, the mapping information indicatinga mapping between one or more data flows within one or more Data NetworkSession (DNS) connections for communicating over the first core networkand one or more corresponding Generic Tunneling Protocol (GTP) tunnelswithin one or more corresponding Packet Data Network (PDN) connectionsfor communicating over a wireless access network utilizing the secondRAT; means for receiving a packet data unit (PDU); if the PDU comprisesan uplink PDU: means for decapsulating the uplink PDU from a GTP tunnelof the one or more GTP tunnels within a PDN connection of the one ormore PDN connections to produce a decapsulated PDU; means for mappingthe decapsulated PDU to a data flow of the one or more data flows basedon the mapping information to produce a data flow PDU; and means forrouting the data flow PDU to a user plane gateway serving the data flowwithin the first core network.
 14. The interworking serving nodeapparatus of claim 13, further comprising: if the PDU comprises adownlink PDU of a data flow of the one or more data flows: means formapping the downlink PDU to a GTP tunnel of the one or more GTP tunnelsand a PDN connection of the one or more PDN connections based on themapping information; means for encapsulating the downlink PDU into a PDNPDU; and means for routing the PDN PDU over the GTP tunnel within thePDN connection to the user equipment via the wireless access network.15. The interworking serving node apparatus of claim 14, wherein: eachof the data flows is associated with a different Internet Protocol (IP)address of the user equipment utilized in the first core network; andeach of the corresponding PDN connections is associated with anadditional different IP address of the user equipment utilized in thewireless access network.
 16. The interworking serving node apparatus ofclaim 13, wherein a first PDN connection comprises two or more of thedata flows, each mapped to a different corresponding GTP tunnel withinthe first PDN connection.
 17. The interworking serving node apparatus ofclaim 13, further comprising: means for receiving additional mappinginformation indicating an additional mapping between a set of two ormore data flows mapped to a first PDN connection to two or moreadditional GTP tunnels within the core network, wherein each of the twoor more additional GTP tunnels provides connectivity to a different userplane gateway in the core network.
 18. The interworking serving nodeapparatus of claim 17, wherein the means for routing the data flow PDUto the user plane gateway further comprises: means for routing the dataflow PDU over an additional GTP tunnel of the one or more additional GTPtunnels based on the additional mapping information.
 19. Anon-transitory computer-readable medium storing computer-executablecode, comprising code for causing an interworking serving node forinterworking between a first core network supporting a first radioaccess technology (RAT) and a second core network supporting a secondRAT to: receive mapping information for a user equipment after handoverof the user equipment from the first RAT to the second RAT, the mappinginformation indicating a mapping between one or more data flows withinone or more Data Network Session (DNS) connections for communicatingover the first core network and one or more corresponding GenericTunneling Protocol (GTP) tunnels within one or more corresponding PacketData Network (PDN) connections for communicating over the wirelessaccess network; receive a packet data unit (PDU); if the PDU comprisesan uplink PDU: decapsulate the uplink PDU from a GTP tunnel of the oneor more GTP tunnels within a PDN connection of the one or more PDNconnections to produce a decapsulated PDU; map the decapsulated PDU to adata flow of the one or more data flows based on the mapping informationto produce a data flow PDU; and route the data flow PDU to a user planegateway serving the data flow within the first core network.
 20. Thenon-transitory computer-readable medium of claim 19, further comprisingcode for causing the interworking serving node to: if the PDU comprisesa downlink PDU of a data flow of the one or more data flows: map thedownlink PDU to a GTP tunnel of the one or more GTP tunnels and a PDNconnection of the one or more PDN connections based on the mappinginformation; encapsulate the downlink PDU into a PDN PDU; and route thePDN PDU over the GTP tunnel within the PDN connection to the userequipment via the wireless access network.
 21. The non-transitorycomputer-readable medium of claim 20, wherein: each of the data flows isassociated with a different Internet Protocol (IP) address of the userequipment utilized in the first core network; and each of thecorresponding PDN connections is associated with an additional differentIP address of the user equipment utilized in the wireless accessnetwork.
 22. The non-transitory computer-readable medium of claim 19,wherein a first PDN connection comprises two or more of the data flows,each mapped to a different corresponding GTP tunnel within the first PDNconnection.
 23. The non-transitory computer-readable medium of claim 19,further comprising code for causing the interworking serving node to:receive additional mapping information indicating an additional mappingbetween a set of two or more data flows mapped to a first PDN connectionto two or more additional GTP tunnels within the core network, whereineach of the two or more additional GTP tunnels provides connectivity toa different user plane gateway in the core network.
 24. Thenon-transitory computer-readable medium of claim 23, further comprisingcode for causing the interworking serving node to: route the data flowPDU over an additional GTP tunnel of the one or more additional GTPtunnels based on the additional mapping information.